- linkend="json-containment"/>.
- describes how these operators can be used to effectively index
- jsonb data.
-
-
Additional <type>jsonb</type> Operators
-
-
- |
- Operator
- Right Operand Type
- Description
- Example
-
-
-
- |
- @>
- jsonb
- Does the left JSON value contain the right JSON
- path/value entries at the top level?
- '{"a":1, "b":2}'::jsonb @> '{"b":2}'::jsonb
-
- |
- <@
- jsonb
- Are the left JSON path/value entries contained at the top level within
- the right JSON value?
- '{"b":2}'::jsonb <@ '{"a":1, "b":2}'::jsonb
-
- |
- ?
- text
- Does the string exist as a top-level
- key within the JSON value?
- '{"a":1, "b":2}'::jsonb ? 'b'
-
- |
- ?|
- text[]
- Do any of these array strings
- exist as top-level keys?
- '{"a":1, "b":2, "c":3}'::jsonb ?| array['b', 'c']
-
- |
- ?&
- text[]
- Do all of these array strings exist
- as top-level keys?
- '["a", "b"]'::jsonb ?& array['a', 'b']
-
- |
- ||
- jsonb
- Concatenate two jsonb values into a new jsonb value
- '["a", "b"]'::jsonb || '["c", "d"]'::jsonb
-
- |
- -
- text
- Delete key/value pair or string
- element from left operand. Key/value pairs are matched based
- on their key value.
- '{"a": "b"}'::jsonb - 'a'
-
- |
- -
- text[]
- Delete multiple key/value pairs or string
- elements from left operand. Key/value pairs are matched based
- on their key value.
- '{"a": "b", "c": "d"}'::jsonb - '{a,c}'::text[]
-
- |
- -
- integer
- Delete the array element with specified index (Negative
- integers count from the end). Throws an error if top level
- container is not an array.
- '["a", "b"]'::jsonb - 1
-
- |
- #-
- text[]
- Delete the field or element with specified path (for
- JSON arrays, negative integers count from the end)
- '["a", {"b":1}]'::jsonb #- '{1,b}'
-
- |
- @?
- jsonpath
- Does JSON path return any item for the specified JSON value?
- '{"a":[1,2,3,4,5]}'::jsonb @? '$.a[*] ? (@ > 2)'
-
- |
- @@
- jsonpath
- Returns the result of JSON path predicate check for the specified JSON value.
- Only the first item of the result is taken into account. If the
- result is not Boolean, then null is returned.
- '{"a":[1,2,3,4,5]}'::jsonb @@ '$.a[*] > 2'
-
-
-
-
-
-
- The || operator concatenates the elements at the top level of
- each of its operands. It does not operate recursively. For example, if
- both operands are objects with a common key field name, the value of the
- field in the result will just be the value from the right hand operand.
-
-
-
-
- The @? and @@ operators suppress
- the following errors: lacking object field or array element, unexpected
- JSON item type, datetime and numeric errors.
- This behavior might be helpful while searching over JSON document
- collections of varying structure.
-
-
-
- shows the functions that are
- available for creating json and jsonb values.
- (There are no equivalent functions for jsonb, of the row_to_json
- and array_to_json functions. However, the to_jsonb
- function supplies much the same functionality as these functions would.)
+ jsonb, though not for json. The comparison
+ operators follow the ordering rules for B-tree operations outlined in
+ .
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
JSON Creation Functions
-
+
<type>json</type> and <type>jsonb</type> Operators
+
|
- Function
- Description
- Example
- Example Result
+ Operator
+
+ Description
+
+ Example(s)
+
+
|
+ json -> integer
+ json
+
+ jsonb -> integer
+ jsonb
+
+ Extracts n'th element of JSON array
+ (array elements are indexed from zero, but negative integers count
+ from the end).
+
+ '[{"a":"foo"},{"b":"bar"},{"c":"baz"}]'::json -> 2
+ {"c":"baz"}
+
+ '[{"a":"foo"},{"b":"bar"},{"c":"baz"}]'::json -> -3
+ {"a":"foo"}
-
- Returns the value as json or jsonb.
- Arrays and composites are converted
- (recursively) to arrays and objects; otherwise, if there is a cast
- from the type to json, the cast function will be used to
- perform the conversion; otherwise, a scalar value is produced.
- For any scalar type other than a number, a Boolean, or a null value,
- the text representation will be used, in such a fashion that it is a
- valid json or jsonb value.
-
- to_json('Fred said "Hi."'::text)
- "Fred said \"Hi.\""
-
- |
-
- array_to_json(anyarray [, pretty_bool])
-
-
- Returns the array as a JSON array. A PostgreSQL multidimensional array
- becomes a JSON array of arrays. Line feeds will be added between
- dimension-1 elements if
pretty_bool is true.
-
- array_to_json('{{1,5},{99,100}}'::int[])
- [[1,5],[99,100]]
+
|
-
- row_to_json(record [, pretty_bool])
-
-
- Returns the row as a JSON object. Line feeds will be added between
- level-1 elements if
pretty_bool is true.
-
- row_to_json(row(1,'foo'))
- {"f1":1,"f2":"foo"}
+ json -> text
+ json
+
+ jsonb -> text
+ jsonb
+
+ Extracts JSON object field with the given key.
+
+ '{"a": {"b":"foo"}}'::json -> 'a'
+ {"b":"foo"}
+
+
|
-
json_build_array(VARIADIC "any")-
jsonb_build_array(VARIADIC "any")+ json ->> integer
+ text
+
+ jsonb ->> integer
+ text
+
+ Extracts n'th element of JSON array,
+ as text.
+
+ '[1,2,3]'::json ->> 2
+ 3
-
- Builds a possibly-heterogeneously-typed JSON array out of a variadic
- argument list.
-
- json_build_array(1,2,'3',4,5)
- [1, 2, "3", 4, 5]
+
|
-
json_build_object(VARIADIC "any")-
jsonb_build_object(VARIADIC "any")+ json ->> text
+ text
+
+ jsonb ->> text
+ text
+
+ Extracts JSON object field with the given key, as text.
+
+ '{"a":1,"b":2}'::json ->> 'b'
+ 2
-
- Builds a JSON object out of a variadic argument list. By
- convention, the argument list consists of alternating
- keys and values.
-
- json_build_object('foo',1,'bar',2)
- {"foo": 1, "bar": 2}
+
|
+ json #> text[]
+ json
+
+ jsonb #> text[]
+ jsonb
+
+ Extracts JSON sub-object at the specified path, where path elements
+ can be either field keys or array indexes.
+
+ '{"a": {"b": ["foo","bar"]}}'::json #> '{a,b,1}'
+ "bar"
-
- Builds a JSON object out of a text array. The array must have either
- exactly one dimension with an even number of members, in which case
- they are taken as alternating key/value pairs, or two dimensions
- such that each inner array has exactly two elements, which
- are taken as a key/value pair.
-
-
json_object('{a, 1, b, "def", c, 3.5}')-
json_object('{{a, 1},{b, "def"},{c, 3.5}}')- {"a": "1", "b": "def", "c": "3.5"}
+
|
-
json_object(keys text[], values text[])-
jsonb_object(keys text[], values text[])+ json #>> text[]
+ text
+
+ jsonb #>> text[]
+ text
+
+ Extracts JSON sub-object at the specified path as text.
+
+ '{"a": {"b": ["foo","bar"]}}'::json #>> '{a,b,1}'
+ bar
-
- This form of json_object takes keys and values pairwise from two separate
- arrays. In all other respects it is identical to the one-argument form.
-
- json_object('{a, b}', '{1,2}')
- {"a": "1", "b": "2"}
- array_to_json and row_to_json have the same
- behavior as to_json except for offering a pretty-printing
- option. The behavior described for to_json likewise applies
- to each individual value converted by the other JSON creation functions.
-
-
-
-
- The extension has a cast
- from hstore to json, so that
- hstore values converted via the JSON creation functions
- will be represented as JSON objects, not as primitive string values.
-
+ The field/element/path extraction operators return NULL, rather than
+ failing, if the JSON input does not have the right structure to match
+ the request; for example if no such key or array element exists.
+
- shows the functions that
- are available for processing json and jsonb values.
+ Some further operators exist only for jsonb, as shown
+ in .
+
+ describes how these operators can be used to effectively search indexed
+ jsonb data.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
jsonb_extract_path_text-
-
-
-
-
-
-
-
-
-
-
json_populate_recordset-
-
-
jsonb_populate_recordset-
-
-
-
-
-
-
json_array_elements_text-
-
-
jsonb_array_elements_text-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
jsonb_path_query_array_tz-
-
-
-
-
jsonb_path_query_first_tz-
-
-
JSON Processing Functions
-
+
Additional <type>jsonb</type> Operators
+
|
- Function
- Return Type
- Description
- Example
- Example Result
+ Operator
+
+ Description
+
+ Example(s)
+
+
|
-
json_array_length(json)-
jsonb_array_length(jsonb)+ jsonb @> jsonb
+ boolean
+
+ Does the first JSON value contain the second?
+ (See for details about containment.)
+
+ '{"a":1, "b":2}'::jsonb @> '{"b":2}'::jsonb
+ t
- int
-
- Returns the number of elements in the outermost JSON array.
-
- json_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')
- 5
+
|
-
-
setof key text, value json-
setof key text, value jsonb+ jsonb <@ jsonb
+ boolean
+
+ Is the first JSON value contained in the second?
+
+ '{"b":2}'::jsonb <@ '{"a":1, "b":2}'::jsonb
+ t
-
- Expands the outermost JSON object into a set of key/value pairs.
-
- select * from json_each('{"a":"foo", "b":"bar"}')
-
- key | value
------+-------
- a | "foo"
- b | "bar"
-
-
+
|
+ jsonb ? text
+ boolean
+
+ Does the text string exist as a top-level key or array element within
+ the JSON value?
+
+ '{"a":1, "b":2}'::jsonb ? 'b'
+ t
+
+ '["a", "b", "c"]'::jsonb ? 'b'
+ t
- setof key text, value text
-
- Expands the outermost JSON object into a set of key/value pairs. The
- returned values will be of type text.
-
- select * from json_each_text('{"a":"foo", "b":"bar"}')
-
- key | value
------+-------
- a | foo
- b | bar
-
-
+
|
-
json_extract_path(from_json json, VARIADIC path_elems text[])-
jsonb_extract_path(from_json jsonb, VARIADIC path_elems text[])-
+ jsonb ?| text[]
+ boolean
+
+ Do any of the strings in the text array exist as top-level keys or
+ array elements?
+
+ '{"a":1, "b":2, "c":3}'::jsonb ?| array['b', 'd']
+ t
-
- Returns JSON value pointed to by path_elems
- (equivalent to #> operator).
-
- json_extract_path('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}','f4')
- {"f5":99,"f6":"foo"}
+
|
-
json_extract_path_text(from_json json, VARIADIC path_elems text[])-
jsonb_extract_path_text(from_json jsonb, VARIADIC path_elems text[])+ jsonb ?& text[]
+ boolean
+
+ Do all of the strings in the text array exist as top-level keys or
+ array elements?
+
+ '["a", "b", "c"]'::jsonb ?& array['a', 'b']
+ t
- text
-
- Returns JSON value pointed to by path_elems
- as text
- (equivalent to #>> operator).
-
- json_extract_path_text('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}','f4', 'f6')
- foo
+
|
-
jsonb_object_keys(jsonb)+ jsonb || jsonb
+ jsonb
+
+ Concatenates two jsonb values.
+ Concatenating two objects generates an object with the union of their
+ keys, taking the second object's value when there are duplicate keys.
+ Does not operate recursively: only the top-level array or object
+ structure is merged.
+
+ '["a", "b"]'::jsonb || '["a", "d"]'::jsonb
+ ["a", "b", "a", "d"]
+
+ '{"a": "b"}'::jsonb || '{"c": "d"}'::jsonb
+ {"a": "b", "c": "d"}
- setof text
-
- Returns set of keys in the outermost JSON object.
-
- json_object_keys('{"f1":"abc","f2":{"f3":"a", "f4":"b"}}')
-
- json_object_keys
-------------------
- f1
- f2
-
-
+
|
-
json_populate_record(base anyelement, from_json json)-
jsonb_populate_record(base anyelement, from_json jsonb)+ jsonb - text
+ jsonb
+
+ Deletes a key (and its value) from a JSON object, or matching string
+ value(s) from a JSON array.
+
+ '{"a": "b", "c": "d"}'::jsonb - 'a'
+ {"c": "d"}
+
+ '["a", "b", "c", "b"]'::jsonb - 'b'
+ ["a", "c"]
- anyelement
-
- Expands the object in from_json to a row
- whose columns match the record type defined by base
- (see note below).
-
- select * from json_populate_record(null::myrowtype, '{"a": 1, "b": ["2", "a b"], "c": {"d": 4, "e": "a b c"}}')
-
- a | b | c
----+-----------+-------------
- 1 | {2,"a b"} | (4,"a b c")
-
-
+
|
-
json_populate_recordset(base anyelement, from_json json)-
jsonb_populate_recordset(base anyelement, from_json jsonb)+ jsonb - text[]
+ jsonb
+
+ Deletes all matching keys or array elements from the left operand.
+
+ '{"a": "b", "c": "d"}'::jsonb - '{a,c}'::text[]
+ {}
- setof anyelement
-
- Expands the outermost array of objects
- in from_json to a set of rows whose
- columns match the record type defined by base (see
- note below).
-
- select * from json_populate_recordset(null::myrowtype, '[{"a":1,"b":2},{"a":3,"b":4}]')
-
- a | b
----+---
- 1 | 2
- 3 | 4
-
-
+
|
-
json_array_elements(json)-
jsonb_array_elements(jsonb)-
+ jsonb - integer
+ jsonb
+
+ Deletes the array element with specified index (negative
+ integers count from the end). Throws an error if JSON value
+ is not an array.
+
+ '["a", "b"]'::jsonb - 1
+ ["a"]
-
- Expands a JSON array to a set of JSON values.
-
- select * from json_array_elements('[1,true, [2,false]]')
-
- value
------------
- 1
- true
- [2,false]
-
-
+
|
-
json_array_elements_text(json)-
jsonb_array_elements_text(jsonb)-
- setof text
-
- Expands a JSON array to a set of text values.
-
- select * from json_array_elements_text('["foo", "bar"]')
-
- value
------------
- foo
- bar
-
-
-
- |
+ jsonb #- text[]
+ jsonb
+
+ Deletes the field or array element at the specified path, where path
+ elements can be either field keys or array indexes.
+
+ '["a", {"b":1}]'::jsonb #- '{1,b}'
+ ["a", {}]
- text
-
- Returns the type of the outermost JSON value as a text string.
- Possible types are
- object, array, string, number,
- boolean, and null.
-
- json_typeof('-123.4')
- number
+
|
+ jsonb @? jsonpath
+ boolean
+
+ Does JSON path return any item for the specified JSON value?
+
+ '{"a":[1,2,3,4,5]}'::jsonb @? '$.a[*] ? (@ > 2)'
+ t
- record
-
- Builds an arbitrary record from a JSON object (see note below). As
- with all functions returning record, the caller must
- explicitly define the structure of the record with an AS
- clause.
-
- select * from json_to_record('{"a":1,"b":[1,2,3],"c":[1,2,3],"e":"bar","r": {"a": 123, "b": "a b c"}}') as x(a int, b text, c int[], d text, r myrowtype)
-
- a | b | c | d | r
----+---------+---------+---+---------------
- 1 | [1,2,3] | {1,2,3} | | (123,"a b c")
-
-
+
|
-
json_to_recordset(json)-
jsonb_to_recordset(jsonb)+ jsonb @@ jsonpath
+ boolean
+
+ Returns the result of a JSON path predicate check for the
+ specified JSON value. Only the first item of the result is taken into
+ account. If the result is not Boolean, then NULL
+ is returned.
+
+ '{"a":[1,2,3,4,5]}'::jsonb @@ '$.a[*] > 2'
+ t
- setof record
-
- Builds an arbitrary set of records from a JSON array of objects (see
- note below). As with all functions returning record, the
- caller must explicitly define the structure of the record with
- an AS clause.
-
- select * from json_to_recordset('[{"a":1,"b":"foo"},{"a":"2","c":"bar"}]') as x(a int, b text);
-
- a | b
----+-----
- 1 | foo
- 2 |
-
-
- |
-
json_strip_nulls(from_json json)-
jsonb_strip_nulls(from_json jsonb)-
-
- Returns from_json
- with all object fields that have null values omitted. Other null values
- are untouched.
-
- json_strip_nulls('[{"f1":1,"f2":null},2,null,3]')
- [{"f1":1},2,null,3]
-
- |
-
jsonb_set(target jsonb, path text[], new_value jsonb , create_missing boolean)-
-
- Returns target
- with the section designated by path
- replaced by new_value, or with
- new_value added if
- create_missing is true (default is
- true) and the item
- designated by path does not exist.
- As with the path oriented operators, negative integers that
- appear in path count from the end
- of JSON arrays.
-
-
jsonb_set('[{"f1":1,"f2":null},2,null,3]', '{0,f1}','[2,3,4]', false)-
jsonb_set('[{"f1":1,"f2":null},2]', '{0,f3}','[2,3,4]')-
-
[{"f1":[2,3,4],"f2":null},2,null,3]-
[{"f1": 1, "f2": null, "f3": [2, 3, 4]}, 2]-
-
- |
-
jsonb_set_lax(target jsonb, path text[], new_value jsonb , create_missing boolean , null_value_treatment text)-
-
- If new_value is not null,
- behaves identically to jsonb_set. Otherwise behaves
- according to the value of null_value_treatment
- which must be one of 'raise_exception',
- 'use_json_null', 'delete_key', or
- 'return_target'. The default is
- 'use_json_null'.
-
-
jsonb_set_lax('[{"f1":1,"f2":null},2,null,3]', '{0,f1}',null)-
jsonb_set_lax('[{"f1":99,"f2":null},2]', '{0,f3}',null, true, 'return_target')-
-
[{"f1":null,"f2":null},2,null,3]-
[{"f1": 99, "f2": null}, 2]-
-
- |
-
- jsonb_insert(target jsonb, path text[], new_value jsonb , insert_after boolean)
-
-
-
- Returns target with
- new_value inserted. If
- target section designated by
- path is in a JSONB array,
- new_value will be inserted before target or
- after if insert_after is true (default is
- false). If target section
- designated by path is in JSONB object,
- new_value will be inserted only if
- target does not exist. As with the path
- oriented operators, negative integers that appear in
- path count from the end of JSON arrays.
-
-
- jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"')
-
- jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"', true)
-
-
-
{"a": [0, "new_value", 1, 2]}-
{"a": [0, 1, "new_value", 2]}-
-
- |
-
jsonb_pretty(from_json jsonb)-
-
- Returns from_json
- as indented JSON text.
-
- jsonb_pretty('[{"f1":1,"f2":null},2,null,3]')
-
-[
- {
- "f1": 1,
- "f2": null
- },
- 2,
- null,
- 3
-]
-
-
-
- |
-
- jsonb_path_exists(target jsonb, path jsonpath , vars jsonb , silent bool)
-
- jsonb_path_exists_tz(target jsonb, path jsonpath , vars jsonb , silent bool)
-
-
- boolean
-
- Checks whether JSON path returns any item for the specified JSON
- value.
-
-
- jsonb_path_exists('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
-
-
-
-
-
- |
-
- jsonb_path_match(target jsonb, path jsonpath , vars jsonb , silent bool)
-
- jsonb_path_match_tz(target jsonb, path jsonpath , vars jsonb , silent bool)
-
-
- boolean
-
- Returns the result of JSON path predicate check for the specified JSON value.
- Only the first item of the result is taken into account. If the
- result is not Boolean, then null is returned.
-
-
- jsonb_path_match('{"a":[1,2,3,4,5]}', 'exists($.a[*] ? (@ >= $min && @ <= $max))', '{"min":2,"max":4}')
-
-
-
-
-
- |
-
- jsonb_path_query(target jsonb, path jsonpath , vars jsonb , silent bool)
-
- jsonb_path_query_tz(target jsonb, path jsonpath , vars jsonb , silent bool)
-
-
- setof jsonb
-
- Gets all JSON items returned by JSON path for the specified JSON
- value.
-
-
- select * from jsonb_path_query('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}');
-
-
-
- jsonb_path_query
-------------------
- 2
- 3
- 4
-
-
-
-
- |
-
- jsonb_path_query_array(target jsonb, path jsonpath , vars jsonb , silent bool)
-
- jsonb_path_query_array_tz(target jsonb, path jsonpath , vars jsonb , silent bool)
-
-
- jsonb
-
- Gets all JSON items returned by JSON path for the specified JSON
- value and wraps result into an array.
-
-
- jsonb_path_query_array('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
-
-
-
-
-
- |
-
- jsonb_path_query_first(target jsonb, path jsonpath , vars jsonb , silent bool)
-
- jsonb_path_query_first_tz(target jsonb, path jsonpath , vars jsonb , silent bool)
-
-
- jsonb
-
- Gets the first JSON item returned by JSON path for the specified JSON
- value. Returns NULL on no results.
-
-
- jsonb_path_query_first('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
-
-
-
-
-
-
- Many of these functions and operators will convert Unicode escapes in
- JSON strings to the appropriate single character. This is a non-issue
- if the input is type jsonb, because the conversion was already
- done; but for json input, this may result in throwing an error,
- as noted in .
-
-
-
-
- The functions
- json[b]_populate_record,
- json[b]_populate_recordset,
- json[b]_to_record and
- json[b]_to_recordset
- operate on a JSON object, or array of objects, and extract the values
- associated with keys whose names match column names of the output row
- type.
- Object fields that do not correspond to any output column name are
- ignored, and output columns that do not match any object field will be
- filled with nulls.
- To convert a JSON value to the SQL type of an output column, the
- following rules are applied in sequence:
-
-
- A JSON null value is converted to a SQL null in all cases.
-
-
-
- If the output column is of type json
- or jsonb, the JSON value is just reproduced exactly.
-
-
-
- If the output column is a composite (row) type, and the JSON value is
- a JSON object, the fields of the object are converted to columns of
- the output row type by recursive application of these rules.
-
-
-
- Likewise, if the output column is an array type and the JSON value is
- a JSON array, the elements of the JSON array are converted to elements
- of the output array by recursive application of these rules.
-
-
-
- Otherwise, if the JSON value is a string literal, the contents of the
- string are fed to the input conversion function for the column's data
- type.
-
-
-
- Otherwise, the ordinary text representation of the JSON value is fed
- to the input conversion function for the column's data type.
-
-
-
-
-
- While the examples for these functions use constants, the typical use
- would be to reference a table in the FROM clause
- and use one of its json or jsonb columns
- as an argument to the function. Extracted key values can then be
- referenced in other parts of the query, like WHERE
- clauses and target lists. Extracting multiple values in this
- way can improve performance over extracting them separately with
- per-key operators.
-
-
-
-
- All the items of the path parameter of jsonb_set
- as well as jsonb_insert except the last item must be present
- in the target. If create_missing is false, all
- items of the path parameter of jsonb_set must be
- present. If these conditions are not met the target is
- returned unchanged.
-
- If the last path item is an object key, it will be created if it
- is absent and given the new value. If the last path item is an array
- index, if it is positive the item to set is found by counting from
- the left, and if negative by counting from the right - -1
- designates the rightmost element, and so on.
- If the item is out of the range -array_length .. array_length -1,
- and create_missing is true, the new value is added at the beginning
- of the array if the item is negative, and at the end of the array if
- it is positive.
-
-
-
-
- The json_typeof function's null return value
- should not be confused with a SQL NULL. While
- calling json_typeof('null'::json) will
- return null, calling json_typeof(NULL::json)
- will return a SQL NULL.
-
-
-
-
- If the argument to json_strip_nulls contains duplicate
- field names in any object, the result could be semantically somewhat
- different, depending on the order in which they occur. This is not an
- issue for jsonb_strip_nulls since jsonb values never have
- duplicate object field names.
-
-
-
-
- The jsonb_path_* functions have optional
- vars and silent arguments.
-
- If the
vars argument is specified, it provides an
- object containing named variables to be substituted into a
- jsonpath expression.
-
- If the
silent argument is specified and has the
- true value, these functions suppress the same errors
- as the @? and @@ operators.
-
-
-
- Some of the jsonb_path_* functions have a
- _tz suffix. These functions have been implemented to
- support comparison of date/time values that involves implicit
- timezone-aware casts. Since operations with time zones are not immutable,
- these functions are qualified as stable. Their counterparts without the
- suffix do not support such casts, so they are immutable and can be used for
- such use-cases as expression indexes
- (see ). There is no difference
- between these functions for other jsonpath operations.
+ The jsonpath operators @?
+ and @@ suppress the following errors: missing object
+ field or array element, unexpected JSON item type, datetime and numeric
+ errors. The jsonpath-related functions described below can
+ also be told to suppress these types of errors. This behavior might be
+ helpful when searching JSON document collections of varying structure.
- See also for the aggregate
- function json_agg which aggregates record
- values as JSON, and the aggregate function
- json_object_agg which aggregates pairs of values
- into a JSON object, and their jsonb equivalents,
- jsonb_agg and jsonb_object_agg.
+ shows the functions that are
+ available for constructing json and jsonb values.
-
-
-
-
The SQL/JSON Path Language
-
-
+
JSON Creation Functions
+
+
+ |
+ Function
+
+ Description
+
+ Example(s)
+
+
+
- SQL/JSON path expressions specify the items to be retrieved
- from the JSON data, similar to XPath expressions used
- for SQL access to XML. In
PostgreSQL,
- path expressions are implemented as the jsonpath
- data type and can use any elements described in
- .
-
-
-
JSON query functions and operators- pass the provided path expression to the path engine
- for evaluation. If the expression matches the queried JSON data,
- the corresponding SQL/JSON item is returned.
- Path expressions are written in the SQL/JSON path language
- and can also include arithmetic expressions and functions.
- Query functions treat the provided expression as a
- text string, so it must be enclosed in single quotes.
-
-
- A path expression consists of a sequence of elements allowed
- by the jsonpath data type.
- The path expression is evaluated from left to right, but
- you can use parentheses to change the order of operations.
- If the evaluation is successful, a sequence of SQL/JSON items
- (SQL/JSON sequence) is produced,
- and the evaluation result is returned to the JSON query function
- that completes the specified computation.
-
-
- To refer to the JSON data to be queried (the
- context item), use the $ sign
- in the path expression. It can be followed by one or more
- accessor operators,
- which go down the JSON structure level by level to retrieve the
- content of context item. Each operator that follows deals with the
- result of the previous evaluation step.
-
-
- For example, suppose you have some JSON data from a GPS tracker that you
- would like to parse, such as:
-{
- "track": {
- "segments": [
- {
- "location": [ 47.763, 13.4034 ],
- "start time": "2018-10-14 10:05:14",
- "HR": 73
- },
- {
- "location": [ 47.706, 13.2635 ],
- "start time": "2018-10-14 10:39:21",
- "HR": 135
- }
- ]
- }
-}
-
-
-
- To retrieve the available track segments, you need to use the
- .key accessor
- operator for all the preceding JSON objects:
-'$.track.segments'
-
-
+
+ |
+
+
+ to_json ( anyelement )
+ json
+
+
+
+ to_jsonb ( anyelement )
+ jsonb
+
+ Converts any SQL value to json or jsonb.
+ Arrays and composites are converted recursively to arrays and
+ objects (multidimensional arrays become arrays of arrays in JSON).
+ Otherwise, if there is a cast from the SQL data type
+ to json, the cast function will be used to perform the
+ conversion;
+ For example, the extension has a cast
+ from hstore to json, so that
+ hstore values converted via the JSON creation functions
+ will be represented as JSON objects, not as primitive string values.
+
+
+ otherwise, a scalar JSON value is produced. For any scalar other than
+ a number, a Boolean, or a null value, the text representation will be
+ used, with escaping as necessary to make it a valid JSON string value.
+
+ to_json('Fred said "Hi."'::text)
+ "Fred said \"Hi.\""
+
+ to_jsonb(row(42, 'Fred said "Hi."'::text))
+ {"f1": 42, "f2": "Fred said \"Hi.\""}
+
+
- If the item to retrieve is an element of an array, you have
- to unnest this array using the [*] operator. For example,
- the following path will return location coordinates for all
- the available track segments:
-'$.track.segments[*].location'
-
-
+ |
+
+
+ array_to_json ( anyarray , boolean )
+ json
+
+ Converts a SQL array to a JSON array. The behavior is the same
+ as to_json except that line feeds will be added
+ between top-level array elements if the optional boolean parameter is
+ true.
+
+ array_to_json('{{1,5},{99,100}}'::int[])
+ [[1,5],[99,100]]
+
+
- To return the coordinates of the first segment only, you can
- specify the corresponding subscript in the []
- accessor operator. Note that the SQL/JSON arrays are 0-relative:
-'$.track.segments[0].location'
-
-
+ |
+
+
+ row_to_json ( record , boolean )
+ json
+
+ Converts a SQL composite value to a JSON object. The behavior is the
+ same as to_json except that line feeds will be
+ added between top-level elements if the optional boolean parameter is
+ true.
+
+ row_to_json(row(1,'foo'))
+ {"f1":1,"f2":"foo"}
+
+
- The result of each path evaluation step can be processed
- by one or more jsonpath operators and methods
- listed in .
- Each method name must be preceded by a dot. For example,
- you can get an array size:
-'$.track.segments.size()'
-
- For more examples of using jsonpath operators
- and methods within path expressions, see
- .
-
+ |
+
+
+ json_build_array ( VARIADIC "any" )
+ json
+
+
+
+ jsonb_build_array ( VARIADIC "any" )
+ jsonb
+
+ Builds a possibly-heterogeneously-typed JSON array out of a variadic
+ argument list. Each argument is converted as
+ per to_json or to_jsonb.
+
+ json_build_array(1,2,'foo',4,5)
+ [1, 2, "foo", 4, 5]
+
+
- When defining the path, you can also use one or more
- filter expressions that work similar to the
- WHERE clause in SQL. A filter expression begins with
- a question mark and provides a condition in parentheses:
+ |
+
+
+ json_build_object ( VARIADIC "any" )
+ json
+
+
+
+ jsonb_build_object ( VARIADIC "any" )
+ jsonb
+
+ Builds a JSON object out of a variadic argument list. By convention,
+ the argument list consists of alternating keys and values. Key
+ arguments are coerced to text; value arguments are converted as
+ per to_json or to_jsonb.
+
+ json_build_object('foo',1,2,row(3,'bar'))
+ {"foo" : 1, "2" : {"f1":3,"f2":"bar"}}
+
+
-? (condition)
-
-
+ |
+
+
+ json_object ( text[] )
+ json
+
+
+
+ jsonb_object ( text[] )
+ jsonb
+
+ Builds a JSON object out of a text array. The array must have either
+ exactly one dimension with an even number of members, in which case
+ they are taken as alternating key/value pairs, or two dimensions
+ such that each inner array has exactly two elements, which
+ are taken as a key/value pair. All values are converted to JSON
+ strings.
+
+ json_object('{a, 1, b, "def", c, 3.5}')
+ {"a" : "1", "b" : "def", "c" : "3.5"}
+
+
json_object('{{a, 1},{b, "def"},{c, 3.5}}')+ {"a" : "1", "b" : "def", "c" : "3.5"}
+
+
- Filter expressions must be specified right after the path evaluation step
- to which they are applied. The result of this step is filtered to include
- only those items that satisfy the provided condition. SQL/JSON defines
- three-valued logic, so the condition can be true, false,
- or unknown. The unknown value
- plays the same role as SQL NULL and can be tested
- for with the is unknown predicate. Further path
- evaluation steps use only those items for which filter expressions
- return true.
-
+ |
+ json_object ( keys text[], values text[] )
+ json
+
+ jsonb_object ( keys text[], values text[] )
+ jsonb
+
+ This form of json_object takes keys and values
+ pairwise from separate text arrays. Otherwise it is identical to
+ the one-argument form.
+
+ json_object('{a, b}', '{1,2}')
+ {"a": "1", "b": "2"}
+
+
+
+
+
- Functions and operators that can be used in filter expressions are listed
- in . The path
- evaluation result to be filtered is denoted by the @
- variable. To refer to a JSON element stored at a lower nesting level,
- add one or more accessor operators after @.
+ shows the functions that
+ are available for processing json and jsonb values.
- Suppose you would like to retrieve all heart rate values higher
- than 130. You can achieve this using the following expression:
-'$.track.segments[*].HR ? (@ > 130)'
-
-
+
JSON Processing Functions
+
+
+ |
+ Function
+
+ Description
+
+ Example(s)
+
+
+
- To get the start time of segments with such values instead, you have to
- filter out irrelevant segments before returning the start time, so the
- filter expression is applied to the previous step, and the path used
- in the condition is different:
+
+ |
+
+
+ json_array_elements ( json )
+ setof json
+
+
+
+ jsonb_array_elements ( jsonb )
+ setof jsonb
+
+ Expands the top-level JSON array into a set of JSON values.
+
+ select * from json_array_elements('[1,true, [2,false]]')
+
-'$.track.segments[*] ? (@.HR > 130)."start time"'
+ value
+-----------
+ 1
+ true
+ [2,false]
-
+
+
- You can use several filter expressions on the same nesting level, if
- required. For example, the following expression selects all segments
- that contain locations with relevant coordinates and high heart rate values:
+ |
+
+
json_array_elements_text+
+ json_array_elements_text ( json )
+ setof text
+
+
+
jsonb_array_elements_text+
+ jsonb_array_elements_text ( jsonb )
+ setof text
+
+ Expands the top-level JSON array into a set of text values.
+
+ select * from json_array_elements_text('["foo", "bar"]')
+
-'$.track.segments[*] ? (@.location[1] < 13.4) ? (@.HR > 130)."start time"'
+ value
+-----------
+ foo
+ bar
-
+
+
- Using filter expressions at different nesting levels is also allowed.
- The following example first filters all segments by location, and then
- returns high heart rate values for these segments, if available:
+ |
+
+
+ json_array_length ( json )
+ integer
+
+
+
+ jsonb_array_length ( jsonb )
+ integer
+
+ Returns the number of elements in the top-level JSON array.
+
+ json_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]')
+ 5
+
+
+
+ |
+
+
+ json_each ( json )
+ setof key text,
+ value json
+
+
+
+ jsonb_each ( jsonb )
+ setof key text,
+ value jsonb
+
+ Expands the top-level JSON object into a set of key/value pairs.
+
+ select * from json_each('{"a":"foo", "b":"bar"}')
+
-'$.track.segments[*] ? (@.location[1] < 13.4).HR ? (@ > 130)'
+ key | value
+-----+-------
+ a | "foo"
+ b | "bar"
-
+
+
- You can also nest filter expressions within each other:
+ |
+
+
+ json_each_text ( json )
+ setof key text,
+ value text
+
+
+
+ jsonb_each_text ( jsonb )
+ setof key text,
+ value text
+
+ Expands the top-level JSON object into a set of key/value pairs.
+ The returned values will be of
+ type text.
+
+ select * from json_each_text('{"a":"foo", "b":"bar"}')
+
-'$.track ? (exists(@.segments[*] ? (@.HR > 130))).segments.size()'
+ key | value
+-----+-------
+ a | foo
+ b | bar
- This expression returns the size of the track if it contains any
- segments with high heart rate values, or an empty sequence otherwise.
-
+
+
-
PostgreSQL's implementation of SQL/JSON path
- language has the following deviations from the SQL/JSON standard:
-
+ |
+
+
+ json_extract_path ( from_json json, VARIADIC path_elems text[] )
+ json
+
+
+
+ jsonb_extract_path ( from_json jsonb, VARIADIC path_elems text[] )
+ jsonb
+
+ Extracts JSON sub-object at the specified path.
+ (This is functionally equivalent to the #>
+ operator, but writing the path out as a variadic list can be more
+ convenient in some cases.)
+
+ json_extract_path('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}', 'f4', 'f6')
+ "foo"
+
+
-
-
- A path expression can be a Boolean predicate, although the SQL/JSON
- standard allows predicates only in filters. This is necessary for
- implementation of the @@ operator. For example,
- the following jsonpath expression is valid in
+ |
+
+
+ json_extract_path_text ( from_json json, VARIADIC path_elems text[] )
+ text
+
+
+
jsonb_extract_path_text+
+ jsonb_extract_path_text ( from_json jsonb, VARIADIC path_elems text[] )
+ text
+
+ Extracts JSON sub-object at the specified path as text.
+ (This is functionally equivalent to the #>>
+ operator.)
+
+ json_extract_path_text('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}', 'f4', 'f6')
+ foo
+
+
+
+ |
+
+
+ json_object_keys ( json )
+ setof text
+
+
+
+ jsonb_object_keys ( jsonb )
+ setof text
+
+ Returns the set of keys in the top-level JSON object.
+
+ select * from json_object_keys('{"f1":"abc","f2":{"f3":"a", "f4":"b"}}')
+
-'$.track.segments[*].HR < 70'
+ json_object_keys
+------------------
+ f1
+ f2
- >
- >
+ >
+ >
-
- There are minor differences in the interpretation of regular
- expression patterns used in like_regex filters, as
- described in .
-
-
-
+ |
+
+
+ json_populate_record ( base anyelement, from_json json )
+ anyelement
+
+
+
+ jsonb_populate_record ( base anyelement, from_json jsonb )
+ anyelement
+
+ Expands the top-level JSON object to a row having the composite type
+ of the base argument. The JSON object
+ is scanned for fields whose names match column names of the output row
+ type, and their values are inserted into those columns of the output.
+ (Fields that do not correspond to any output column name are ignored.)
+ In typical use, the value of base is just
+ NULL, which means that any output columns that do
+ not match any object field will be filled with nulls. However,
+ if base isn't NULL then
+ the values it contains will be used for unmatched columns.
+
+ To convert a JSON value to the SQL type of an output column, the
+ following rules are applied in sequence:
+
+
+ A JSON null value is converted to a SQL null in all cases.
+
+
+
+ If the output column is of type json
+ or jsonb, the JSON value is just reproduced exactly.
+
+
+
+ If the output column is a composite (row) type, and the JSON value
+ is a JSON object, the fields of the object are converted to columns
+ of the output row type by recursive application of these rules.
+
+
+
+ Likewise, if the output column is an array type and the JSON value
+ is a JSON array, the elements of the JSON array are converted to
+ elements of the output array by recursive application of these
+ rules.
+
+
+
+ Otherwise, if the JSON value is a string, the contents of the
+ string are fed to the input conversion function for the column's
+ data type.
+
+
+
+ Otherwise, the ordinary text representation of the JSON value is
+ fed to the input conversion function for the column's data type.
+
+
+
+
+ While the example below uses a constant JSON value, typical use would
+ be to reference a json or jsonb column
+ laterally from another table in the query's FROM
+ clause. Writing json_populate_record in
+ the FROM clause is good practice, since all of the
+ extracted columns are available for use without duplicate function
+ calls.
+
+ select * from json_populate_record(null::myrowtype, '{"a": 1, "b": ["2", "a b"], "c": {"d": 4, "e": "a b c"}}')
+
+ a | b | c
+---+-----------+-------------
+ 1 | {2,"a b"} | (4,"a b c")
+
+
+
-
-
Strict and Lax Modes
- When you query JSON data, the path expression may not match the
- actual JSON data structure. An attempt to access a non-existent
- member of an object or element of an array results in a
- structural error. SQL/JSON path expressions have two modes
- of handling structural errors:
-
+ |
+
+
json_populate_recordset+
+ json_populate_recordset ( base anyelement, from_json json )
+ setof anyelement
+
+
+
jsonb_populate_recordset+
+ jsonb_populate_recordset ( base anyelement, from_json jsonb )
+ setof anyelement
+
+ Expands the top-level JSON array of objects to a set of rows having
+ the composite type of the base argument.
+ Each element of the JSON array is processed as described above
+ for json[b]_populate_record.
+
+ select * from json_populate_recordset(null::myrowtype, '[{"a":1,"b":2},{"a":3,"b":4}]')
+
+ a | b
+---+---
+ 1 | 2
+ 3 | 4
+
+
+
+
+ |
+
+
+ json_to_record ( json )
+ record
+
+
+
+ jsonb_to_record ( jsonb )
+ record
+
+ Expands the top-level JSON object to a row having the composite type
+ defined by an AS clause. (As with all functions
+ returning record, the calling query must explicitly
+ define the structure of the record with an AS
+ clause.) The output record is filled from fields of the JSON object,
+ in the same way as described above
+ for json[b]_populate_record. Since there is no
+ input record value, unmatched columns are always filled with nulls.
+
+ select * from json_to_record('{"a":1,"b":[1,2,3],"c":[1,2,3],"e":"bar","r": {"a": 123, "b": "a b c"}}') as x(a int, b text, c int[], d text, r myrowtype)
+
+ a | b | c | d | r
+---+---------+---------+---+---------------
+ 1 | [1,2,3] | {1,2,3} | | (123,"a b c")
+
+
+
+
+ |
+
+
+ json_to_recordset ( json )
+ setof record
+
+
+
+ jsonb_to_recordset ( jsonb )
+ setof record
+
+ Expands the top-level JSON array of objects to a set of rows having
+ the composite type defined by an AS clause. (As
+ with all functions returning record, the calling query
+ must explicitly define the structure of the record with
+ an AS clause.) Each element of the JSON array is
+ processed as described above
+ for json[b]_populate_record.
+
+ select * from json_to_recordset('[{"a":1,"b":"foo"},{"a":"2","c":"bar"}]') as x(a int, b text)
+
+ a | b
+---+-----
+ 1 | foo
+ 2 |
+
+
+
+
+ |
+
+
+ jsonb_set ( target jsonb, path text[], new_value jsonb , create_if_missing boolean )
+ jsonb
+
+ Returns target
+ with the item designated by path
+ replaced by new_value, or with
+ new_value added if
+ create_if_missing is true (which is the
+ default) and the item designated by path
+ does not exist.
+ All earlier steps in the path must exist, or
+ the target is returned unchanged.
+ As with the path oriented operators, negative integers that
+ appear in the path count from the end
+ of JSON arrays.
+ If the last path step is an array index that is out of range,
+ and create_if_missing is true, the new
+ value is added at the beginning of the array if the index is negative,
+ or at the end of the array if it is positive.
+
+ jsonb_set('[{"f1":1,"f2":null},2,null,3]', '{0,f1}','[2,3,4]', false)
+ [{"f1": [2, 3, 4], "f2": null}, 2, null, 3]
+
+ jsonb_set('[{"f1":1,"f2":null},2]', '{0,f3}','[2,3,4]')
+ [{"f1": 1, "f2": null, "f3": [2, 3, 4]}, 2]
+
+
+
+ |
+
+
+ jsonb_set_lax ( target jsonb, path text[], new_value jsonb , create_if_missing boolean , null_value_treatment text )
+ jsonb
+
+ If new_value is not NULL,
+ behaves identically to jsonb_set. Otherwise behaves
+ according to the value
+ of null_value_treatment which must be one
+ of 'raise_exception',
+ 'use_json_null', 'delete_key', or
+ 'return_target'. The default is
+ 'use_json_null'.
+
+ jsonb_set_lax('[{"f1":1,"f2":null},2,null,3]', '{0,f1}',null)
+ [{"f1":null,"f2":null},2,null,3]
+
+ jsonb_set_lax('[{"f1":99,"f2":null},2]', '{0,f3}',null, true, 'return_target')
+ [{"f1": 99, "f2": null}, 2]
+
+
+
+ |
+
+
+ jsonb_insert ( target jsonb, path text[], new_value jsonb , insert_after boolean )
+ jsonb
+
+ Returns target
+ with new_value inserted. If the item
+ designated by the path is an array
+ element, new_value will be inserted before
+ that item if insert_after is false (which
+ is the default), or after it
+ if insert_after is true. If the item
+ designated by the path is an object
+ field, new_value will be inserted only if
+ the object does not already contain that key.
+ All earlier steps in the path must exist, or
+ the target is returned unchanged.
+ As with the path oriented operators, negative integers that
+ appear in the path count from the end
+ of JSON arrays.
+ If the last path step is an array index that is out of range, the new
+ value is added at the beginning of the array if the index is negative,
+ or at the end of the array if it is positive.
+
+ jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"')
+ {"a": [0, "new_value", 1, 2]}
+
+ jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"', true)
+ {"a": [0, 1, "new_value", 2]}
+
+
+
+ |
+
+
+ json_strip_nulls ( json )
+ json
+
+
+
+ jsonb_strip_nulls ( jsonb )
+ jsonb
+
+ Deletes all object fields that have null values from the given JSON
+ value, recursively. Null values that are not object fields are
+ untouched.
+
+ json_strip_nulls('[{"f1":1,"f2":null},2,null,3]')
+ [{"f1":1},2,null,3]
+
+
+
+ |
+
+
+ jsonb_path_exists ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ boolean
+
+ Checks whether the JSON path returns any item for the specified JSON
+ value.
+ If the vars argument is specified, it must
+ be a JSON object, and its fields provide named values to be
+ substituted into the jsonpath expression.
+ If the silent argument is specified and
+ is true, the function suppresses the same errors
+ as the @? and @@ operators do.
+
+ jsonb_path_exists('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
+ t
+
+
+
+ |
+
+
+ jsonb_path_match ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ boolean
+
+ Returns the result of a JSON path predicate check for the specified
+ JSON value. Only the first item of the result is taken into account.
+ If the result is not Boolean, then NULL is returned.
+ The optional vars
+ and silent arguments act the same as
+ for jsonb_path_exists.
+
+ jsonb_path_match('{"a":[1,2,3,4,5]}', 'exists($.a[*] ? (@ >= $min && @ <= $max))', '{"min":2,"max":4}')
+ t
+
+
+
+ |
+
+
+ jsonb_path_query ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ setof jsonb
+
+ Returns all JSON items returned by the JSON path for the specified
+ JSON value.
+ The optional vars
+ and silent arguments act the same as
+ for jsonb_path_exists.
+
+ select * from jsonb_path_query('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
+
+ jsonb_path_query
+------------------
+ 2
+ 3
+ 4
+
+
+
+
+ |
+
+
+ jsonb_path_query_array ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ jsonb
+
+ Returns all JSON items returned by the JSON path for the specified
+ JSON value, as a JSON array.
+ The optional vars
+ and silent arguments act the same as
+ for jsonb_path_exists.
+
+ jsonb_path_query_array('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
+ [2, 3, 4]
+
+
+
+ |
+
+
+ jsonb_path_query_first ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ jsonb
+
+ Returns the first JSON item returned by the JSON path for the
+ specified JSON value. Returns NULL if there are no
+ results.
+ The optional vars
+ and silent arguments act the same as
+ for jsonb_path_exists.
+
+ jsonb_path_query_first('{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}')
+ 2
+
+
+
+ |
+
+
+ jsonb_path_exists_tz ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ boolean
+
+
+
+ jsonb_path_match_tz ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ boolean
+
+
+
+ jsonb_path_query_tz ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ setof jsonb
+
+
+
jsonb_path_query_array_tz+
+ jsonb_path_query_array_tz ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ jsonb
+
+
+
jsonb_path_query_first_tz+
+ jsonb_path_query_first_tz ( target jsonb, path jsonpath , vars jsonb , silent boolean )
+ jsonb
+
+ These functions act like their counterparts described above without
+ the _tz suffix, except that these functions support
+ comparisons of date/time values that require timezone-aware
+ conversions. The example below requires interpretation of the
+ date-only value 2015-08-02 as a timestamp with time
+ zone, so the result depends on the current
+ setting. Due to this dependency, these
+ functions are marked as stable, which means these functions cannot be
+ used in indexes. Their counterparts are immutable, and so can be used
+ in indexes; but they will throw errors if asked to make such
+ comparisons.
+
+ jsonb_path_exists_tz('["2015-08-01 12:00:00 -05"]', '$[*] ? (@.datetime() < "2015-08-02".datetime())')
+ t
+
+
+
+ |
+
+
+ jsonb_pretty ( jsonb )
+ text
+
+ Converts the given JSON value to pretty-printed, indented text.
+
+ jsonb_pretty('[{"f1":1,"f2":null},2]')
+
+[
+ {
+ "f1": 1,
+ "f2": null
+ },
+ 2
+]
+
+
+
+
+ |
+
+
+ json_typeof ( json )
+ text
+
+
+
+ jsonb_typeof ( jsonb )
+ text
+
+ Returns the type of the top-level JSON value as a text string.
+ Possible types are
+ object, array,
+ string, number,
+ boolean, and null.
+ (The null result should not be confused
+ with a SQL NULL; see the examples.)
+
+ json_typeof('-123.4')
+ number
+
+ json_typeof('null'::json)
+ null
+
+ json_typeof(NULL::json) IS NULL
+ t
+
+
+
+
+
+
+ See also for the aggregate
+ function json_agg which aggregates record
+ values as JSON, the aggregate function
+ json_object_agg which aggregates pairs of values
+ into a JSON object, and their jsonb equivalents,
+ jsonb_agg and jsonb_object_agg.
+
+
+
+
+
The SQL/JSON Path Language
+
+
+
+
+ SQL/JSON path expressions specify the items to be retrieved
+ from the JSON data, similar to XPath expressions used
+ for SQL access to XML. In
PostgreSQL,
+ path expressions are implemented as the jsonpath
+ data type and can use any elements described in
+ .
+
+
+ JSON query functions and operators
+ pass the provided path expression to the path engine
+ for evaluation. If the expression matches the queried JSON data,
+ the corresponding JSON item, or set of items, is returned.
+ Path expressions are written in the SQL/JSON path language
+ and can include arithmetic expressions and functions.
+
+
+ A path expression consists of a sequence of elements allowed
+ by the jsonpath data type.
+ The path expression is normally evaluated from left to right, but
+ you can use parentheses to change the order of operations.
+ If the evaluation is successful, a sequence of JSON items is produced,
+ and the evaluation result is returned to the JSON query function
+ that completes the specified computation.
+
+
+ To refer to the JSON value being queried (the
+ context item), use the $ variable
+ in the path expression. It can be followed by one or more
+ accessor operators,
+ which go down the JSON structure level by level to retrieve sub-items
+ of the context item. Each operator that follows deals with the
+ result of the previous evaluation step.
+
+
+ For example, suppose you have some JSON data from a GPS tracker that you
+ would like to parse, such as:
+{
+ "track": {
+ "segments": [
+ {
+ "location": [ 47.763, 13.4034 ],
+ "start time": "2018-10-14 10:05:14",
+ "HR": 73
+ },
+ {
+ "location": [ 47.706, 13.2635 ],
+ "start time": "2018-10-14 10:39:21",
+ "HR": 135
+ }
+ ]
+ }
+}
+
+
+
+ To retrieve the available track segments, you need to use the
+ .key accessor
+ operator to descend through surrounding JSON objects:
+$.track.segments
+
+
+
+ To retrieve the contents of an array, you typically use the
+ [*] operator. For example,
+ the following path will return the location coordinates for all
+ the available track segments:
+$.track.segments[*].location
+
+
+
+ To return the coordinates of the first segment only, you can
+ specify the corresponding subscript in the []
+ accessor operator. Recall that JSON array indexes are 0-relative:
+$.track.segments[0].location
+
+
+
+ The result of each path evaluation step can be processed
+ by one or more jsonpath operators and methods
+ listed in .
+ Each method name must be preceded by a dot. For example,
+ you can get the size of an array:
+$.track.segments.size()
+
+ More examples of using jsonpath operators
+ and methods within path expressions appear below in
+ .
+
+
+ When defining a path, you can also use one or more
+ filter expressions that work similarly to the
+ WHERE clause in SQL. A filter expression begins with
+ a question mark and provides a condition in parentheses:
+
+? (condition)
+
+
+
+ Filter expressions must be written just after the path evaluation step
+ to which they should apply. The result of that step is filtered to include
+ only those items that satisfy the provided condition. SQL/JSON defines
+ three-valued logic, so the condition can be true, false,
+ or unknown. The unknown value
+ plays the same role as SQL NULL and can be tested
+ for with the is unknown predicate. Further path
+ evaluation steps use only those items for which the filter expression
+ returned true.
+
+
+ The functions and operators that can be used in filter expressions are
+ listed in . Within a
+ filter expression, the @ variable denotes the value
+ being filtered (i.e., one result of the preceding path step). You can
+ write accessor operators after @ to retrieve component
+ items.
+
+
+ For example, suppose you would like to retrieve all heart rate values higher
+ than 130. You can achieve this using the following expression:
+$.track.segments[*].HR ? (@ > 130)
+
+
+
+ To get the start times of segments with such values, you have to
+ filter out irrelevant segments before returning the start times, so the
+ filter expression is applied to the previous step, and the path used
+ in the condition is different:
+$.track.segments[*] ? (@.HR > 130)."start time"
+
+
+
+ You can use several filter expressions in sequence, if required. For
+ example, the following expression selects start times of all segments that
+ contain locations with relevant coordinates and high heart rate values:
+$.track.segments[*] ? (@.location[1] < 13.4) ? (@.HR > 130)."start time"
+
+
+
+ Using filter expressions at different nesting levels is also allowed.
+ The following example first filters all segments by location, and then
+ returns high heart rate values for these segments, if available:
+$.track.segments[*] ? (@.location[1] < 13.4).HR ? (@ > 130)
+
+
+
+ You can also nest filter expressions within each other:
+$.track ? (exists(@.segments[*] ? (@.HR > 130))).segments.size()
+
+ This expression returns the size of the track if it contains any
+ segments with high heart rate values, or an empty sequence otherwise.
+
+
+
PostgreSQL's implementation of the SQL/JSON path
+ language has the following deviations from the SQL/JSON standard:
+
+
+
+
+ A path expression can be a Boolean predicate, although the SQL/JSON
+ standard allows predicates only in filters. This is necessary for
+ implementation of the @@ operator. For example,
+ the following jsonpath expression is valid in
+$.track.segments[*].HR < 70
+
+
+
+
+
+ There are minor differences in the interpretation of regular
+ expression patterns used in like_regex filters, as
+ described in .
+
+
+
+
+
+
Strict and Lax Modes
+ When you query JSON data, the path expression may not match the
+ actual JSON data structure. An attempt to access a non-existent
+ member of an object or element of an array results in a
+ structural error. SQL/JSON path expressions have two modes
+ of handling structural errors:
+
+
+
+
+ lax (default) — the path engine implicitly adapts
+ the queried data to the specified path.
+ Any remaining structural errors are suppressed and converted
+ to empty SQL/JSON sequences.
+
+
+
+ strict — if a structural error occurs, an error is raised.
+
+
+
+
+ The lax mode facilitates matching of a JSON document structure and path
+ expression if the JSON data does not conform to the expected schema.
+ If an operand does not match the requirements of a particular operation,
+ it can be automatically wrapped as an SQL/JSON array or unwrapped by
+ converting its elements into an SQL/JSON sequence before performing
+ this operation. Besides, comparison operators automatically unwrap their
+ operands in the lax mode, so you can compare SQL/JSON arrays
+ out-of-the-box. An array of size 1 is considered equal to its sole element.
+ Automatic unwrapping is not performed only when:
+
+
+ The path expression contains type() or
+ size() methods that return the type
+ and the number of elements in the array, respectively.
+
+
+
+ The queried JSON data contain nested arrays. In this case, only
+ the outermost array is unwrapped, while all the inner arrays
+ remain unchanged. Thus, implicit unwrapping can only go one
+ level down within each path evaluation step.
+
+
+
+
+
+ For example, when querying the GPS data listed above, you can
+ abstract from the fact that it stores an array of segments
+ when using the lax mode:
+lax $.track.segments.location
+
+
+
+ In the strict mode, the specified path must exactly match the structure of
+ the queried JSON document to return an SQL/JSON item, so using this
+ path expression will cause an error. To get the same result as in
+ the lax mode, you have to explicitly unwrap the
+ segments array:
+strict $.track.segments[*].location
+
+
+
+
+
+
+
SQL/JSON Path Operators and Methods
+
+ shows the operators and
+ methods available in jsonpath. Note that while the unary
+ operators and methods can be applied to multiple values resulting from a
+ preceding path step, the binary operators (addition etc.) can only be
+ applied to single values.
+
+
+
<type>jsonpath</type> Operators and Methods
+
+
+ |
+ Operator/Method
+
+ Description
+
+ Example(s)
+
+
+
+
+
+ |
+ number + number
+ number
+
+ Addition
+
+ jsonb_path_query('[2]', '$[0] + 3')
+ 5
+
+
+
+ |
+ + number
+ number
+
+ Unary plus (no operation); unlike addition, this can iterate over
+ multiple values
+
+ jsonb_path_query_array('{"x": [2,3,4]}', '+ $.x')
+ [2, 3, 4]
+
+
+
+ |
+ number - number
+ number
+
+ Subtraction
+
+ jsonb_path_query('[2]', '7 - $[0]')
+ 5
+
+
+
+ |
+ - number
+ number
+
+ Negation; unlike subtraction, this can iterate over
+ multiple values
+
+ jsonb_path_query_array('{"x": [2,3,4]}', '- $.x')
+ [-2, -3, -4]
+
+
+
+ |
+ number * number
+ number
+
+ Multiplication
+
+ jsonb_path_query('[4]', '2 * $[0]')
+ 8
+
+
+
+ |
+ number / number
+ number
+
+ Division
+
+ jsonb_path_query('[8.5]', '$[0] / 2')
+ 4.2500000000000000
+
+
+
+ |
+ number % number
+ number
+
+ Modulo (remainder)
+
+ jsonb_path_query('[32]', '$[0] % 10')
+ 2
+
+
+
+ |
+ value . type()
+ string
+
+ Type of the JSON item (see json_typeof)
+
+ jsonb_path_query_array('[1, "2", {}]', '$[*].type()')
+ ["number", "string", "object"]
+
+
+
+ |
+ value . size()
+ number
+
+ Size of the JSON item (number of array elements, or 1 if not an
+ array)
+
+ jsonb_path_query('{"m": [11, 15]}', '$.m.size()')
+ 2
+
+
+
+ |
+ value . double()
+ number
+
+ Approximate floating-point number converted from a JSON number or
+ string
+
+ jsonb_path_query('{"len": "1.9"}', '$.len.double() * 2')
+ 3.8
+
+
+
+ |
+ number . ceiling()
+ number
+
+ Nearest integer greater than or equal to the given number
+
+ jsonb_path_query('{"h": 1.3}', '$.h.ceiling()')
+ 2
+
+
+
+ |
+ number . floor()
+ number
+
+ Nearest integer less than or equal to the given number
+
+ jsonb_path_query('{"h": 1.7}', '$.h.floor()')
+ 1
+
+
+
+ |
+ number . abs()
+ number
+
+ Absolute value of the given number
+
+ jsonb_path_query('{"z": -0.3}', '$.z.abs()')
+ 0.3
+
+
+
+ |
+ string . datetime()
+ datetime_type
+ (see note)
+
+ Date/time value converted from a string
+
+ jsonb_path_query('["2015-8-1", "2015-08-12"]', '$[*] ? (@.datetime() < "2015-08-2".datetime())')
+ "2015-8-1"
+
+
+
+ |
+ string . datetime(template)
+ datetime_type
+ (see note)
+
+ Date/time value converted from a string using the
+ specified to_timestamp template
+
+ jsonb_path_query_array('["12:30", "18:40"]', '$[*].datetime("HH24:MI")')
+ ["12:30:00", "18:40:00"]
+
+
+
+ |
+ object . keyvalue()
+ array
+
+ The object's key-value pairs, represented as an array of objects
+ containing three fields: "key",
+ "value", and "id";
+ "id" is a unique identifier of the object the
+ key-value pair belongs to
+
+ jsonb_path_query_array('{"x": "20", "y": 32}', '$.keyvalue()')
+ [{"id": 0, "key": "x", "value": "20"}, {"id": 0, "key": "y", "value": 32}]
+
+
+
+
+
+
+
+ The result type of the datetime() and
+ datetime(template)
+ methods can be date, timetz, time,
+ timestamptz, or timestamp.
+ Both methods determine their result type dynamically.
+
+ The datetime() method sequentially tries to
+ match its input string to the ISO formats
+ for date, timetz, time,
+ timestamptz, and timestamp. It stops on
+ the first matching format and emits the corresponding data type.
+
+ The datetime(template)
+ method determines the result type according to the fields used in the
+ provided template string.
+
+ The datetime() and
+ datetime(template) methods
+ use the same parsing rules as the to_timestamp SQL
+ function does (see ), with three
+ exceptions. First, these methods don't allow unmatched template
+ patterns. Second, only the following separators are allowed in the
+ template string: minus sign, period, solidus (slash), comma, apostrophe,
+ semicolon, colon and space. Third, separators in the template string
+ must exactly match the input string.
+
+ If different date/time types need to be compared, an implicit cast is
+ applied. A date value can be cast to timestamp
+ or timestamptz, timestamp can be cast to
+ timestamptz, and time to timetz.
+ However, all but the first of these conversions depend on the current
+ setting, and thus can only be performed
+ within timezone-aware jsonpath functions.
+
+
+
+ shows the available
+ filter expression elements.
+
+
+
<type>jsonpath</type> Filter Expression Elements
+
+
+ |
+ Predicate/Value
+
+ Description
+
+ Example(s)
+
+
+
+
+
+ |
+ value == value
+ boolean
+
+ Equality comparison (this, and the other comparison operators, work on
+ all JSON scalar values)
+
+ jsonb_path_query_array('[1, "a", 1, 3]', '$[*] ? (@ == 1)')
+ [1, 1]
+
+ jsonb_path_query_array('[1, "a", 1, 3]', '$[*] ? (@ == "a")')
+ ["a"]
+
+
+
+ |
+ value != value
+ boolean
+
+ value <> value
+ boolean
+
+ Non-equality comparison
+
+ jsonb_path_query_array('[1, 2, 1, 3]', '$[*] ? (@ != 1)')
+ [2, 3]
+
+ jsonb_path_query_array('["a", "b", "c"]', '$[*] ? (@ <> "b")')
+ ["a", "c"]
+
+
+
+ |
+ value < value
+ boolean
+
+ Less-than comparison
+
+ jsonb_path_query_array('[1, 2, 3]', '$[*] ? (@ < 2)')
+ [1]
+
+
+
+ |
+ value <= value
+ boolean
+
+ Less-than-or-equal-to comparison
+
+ jsonb_path_query_array('["a", "b", "c"]', '$[*] ? (@ <= "b")')
+ ["a", "b"]
+
+
+
+ |
+ value > value
+ boolean
+
+ Greater-than comparison
+
+ jsonb_path_query_array('[1, 2, 3]', '$[*] ? (@ > 2)')
+ [3]
+
+
+
+ |
+ value >= value
+ boolean
+
+ Greater-than-or-equal-to comparison
+
+ jsonb_path_query_array('[1, 2, 3]', '$[*] ? (@ >= 2)')
+ [2, 3]
+
+
+
+ |
+ true
+ boolean
+
+ JSON constant true
+
+ jsonb_path_query('[{"name": "John", "parent": false}, {"name": "Chris", "parent": true}]', '$[*] ? (@.parent == true)')
+ {"name": "Chris", "parent": true}
+
+
+
+ |
+ false
+ boolean
+
+ JSON constant false
+
+ jsonb_path_query('[{"name": "John", "parent": false}, {"name": "Chris", "parent": true}]', '$[*] ? (@.parent == false)')
+ {"name": "John", "parent": false}
+
+
+
+ |
+ null
+ value
+
+ JSON constant null (note that, unlike in SQL,
+ comparison to null works normally)
+
+ jsonb_path_query('[{"name": "Mary", "job": null}, {"name": "Michael", "job": "driver"}]', '$[*] ? (@.job == null) .name')
+ "Mary"
+
+
+
+ |
+ boolean && boolean
+ boolean
+
+ Boolean AND
+
+ jsonb_path_query('[1, 3, 7]', '$[*] ? (@ > 1 && @ < 5)')
+ 3
+
+
+
+ |
+ boolean || boolean
+ boolean
+
+ Boolean OR
+
+ jsonb_path_query('[1, 3, 7]', '$[*] ? (@ < 1 || @ > 5)')
+ 7
+
+
+
+ |
+ ! boolean
+ boolean
+
+ Boolean NOT
+
+ jsonb_path_query('[1, 3, 7]', '$[*] ? (!(@ < 5))')
+ 7
+
+
-
-
- lax (default) — the path engine implicitly adapts
- the queried data to the specified path.
- Any remaining structural errors are suppressed and converted
- to empty SQL/JSON sequences.
-
-
-
- strict — if a structural error occurs, an error is raised.
-
-
-
+ |
+ boolean is unknown
+ boolean
+
+ Tests whether a Boolean condition is unknown.
+
+ jsonb_path_query('[-1, 2, 7, "foo"]', '$[*] ? ((@ > 0) is unknown)')
+ "foo"
+
+
- The lax mode facilitates matching of a JSON document structure and path
- expression if the JSON data does not conform to the expected schema.
- If an operand does not match the requirements of a particular operation,
- it can be automatically wrapped as an SQL/JSON array or unwrapped by
- converting its elements into an SQL/JSON sequence before performing
- this operation. Besides, comparison operators automatically unwrap their
- operands in the lax mode, so you can compare SQL/JSON arrays
- out-of-the-box. An array of size 1 is considered equal to its sole element.
- Automatic unwrapping is not performed only when:
-
-
- The path expression contains type() or
- size() methods that return the type
- and the number of elements in the array, respectively.
-
-
-
- The queried JSON data contain nested arrays. In this case, only
- the outermost array is unwrapped, while all the inner arrays
- remain unchanged. Thus, implicit unwrapping can only go one
- level down within each path evaluation step.
-
-
-
-
+ |
+ string like_regex string flag string
+ boolean
+
+ Tests whether the first operand matches the regular expression
+ given by the second operand, optionally with modifications
+ described by a string of flag characters (see
+ ).
+
+ jsonb_path_query_array('["abc", "abd", "aBdC", "abdacb", "babc"]', '$[*] ? (@ like_regex "^ab.*c")')
+ ["abc", "abdacb"]
+
+ jsonb_path_query_array('["abc", "abd", "aBdC", "abdacb", "babc"]', '$[*] ? (@ like_regex "^ab.*c" flag "i")')
+ ["abc", "aBdC", "abdacb"]
+
+
- For example, when querying the GPS data listed above, you can
- abstract from the fact that it stores an array of segments
- when using the lax mode:
-'lax $.track.segments.location'
-
-
+ |
+ string starts with string
+ boolean
+
+ Tests whether the second operand is an initial substring of the first
+ operand.
+
+ jsonb_path_query('["John Smith", "Mary Stone", "Bob Johnson"]', '$[*] ? (@ starts with "John")')
+ "John Smith"
+
+
- In the strict mode, the specified path must exactly match the structure of
- the queried JSON document to return an SQL/JSON item, so using this
- path expression will cause an error. To get the same result as in
- the lax mode, you have to explicitly unwrap the
- segments array:
-'strict $.track.segments[*].location'
-
-
+ |
+ exists ( path_expression )
+ boolean
+
+ Tests whether a path expression matches at least one SQL/JSON item.
+ Returns unknown if the path expression would result
+ in an error; the second example uses this to avoid a no-such-key error
+ in strict mode.
+
+ jsonb_path_query('{"x": [1, 2], "y": [2, 4]}', 'strict $.* ? (exists (@ ? (@[*] > 2)))')
+ [2, 4]
+
+ jsonb_path_query_array('{"value": 41}', 'strict $ ? (exists (@.name)) .name')
+ []
+
+
+
+
+
-
Regular Expressions
+
<span class="marked">SQL/JSON </span>Regular Expressions
following SQL/JSON path query would case-insensitively match all
strings in an array that start with an English vowel:
-'$[*] ? (@ like_regex "^[aeiou]" flag "i")'
+$[*] ? (@ like_regex "^[aeiou]" flag "i")
backslashes you want to use in the regular expression must be doubled.
For example, to match strings that contain only digits:
-'$ ? (@ like_regex "^\\d+$")'
+$ ? (@ like_regex "^\\d+$")
-
-
-
-
-
SQL/JSON Path Operators and Methods
-
- shows the operators and
- methods available in
jsonpath.
- linkend="functions-sqljson-filter-ex-table"/> shows the available filter
- expression elements.
-
-
-
<type>jsonpath</type> Operators and Methods
-
-
- |
- Operator/Method
- Description
- Example JSON
- Example Query
- Result
-
-
-
- |
- + (unary)
- Plus operator that iterates over the SQL/JSON sequence
- {"x": [2.85, -14.7, -9.4]}
- + $.x.floor()
- 2, -15, -10
-
- |
- - (unary)
- Minus operator that iterates over the SQL/JSON sequence
- {"x": [2.85, -14.7, -9.4]}
- - $.x.floor()
- -2, 15, 10
-
- |
- + (binary)
- Addition
- [2]
- 2 + $[0]
- 4
-
- |
- - (binary)
- Subtraction
- [2]
- 4 - $[0]
- 2
-
- |
- *
- Multiplication
- [4]
- 2 * $[0]
- 8
-
- |
- /
- Division
- [8]
- $[0] / 2
- 4
-
- |
- %
- Modulus
- [32]
- $[0] % 10
- 2
-
- |
- type()
- Type of the SQL/JSON item
- [1, "2", {}]
- $[*].type()
- "number", "string", "object"
-
- |
- size()
- Size of the SQL/JSON item
- {"m": [11, 15]}
- $.m.size()
- 2
-
- |
- double()
- Approximate floating-point number converted from an SQL/JSON number or a string
- {"len": "1.9"}
- $.len.double() * 2
- 3.8
-
- |
- ceiling()
- Nearest integer greater than or equal to the SQL/JSON number
- {"h": 1.3}
- $.h.ceiling()
- 2
-
- |
- floor()
- Nearest integer less than or equal to the SQL/JSON number
- {"h": 1.3}
- $.h.floor()
- 1
-
- |
- abs()
- Absolute value of the SQL/JSON number
- {"z": -0.3}
- $.z.abs()
- 0.3
-
- |
- datetime()
- Date/time value converted from a string
- ["2015-8-1", "2015-08-12"]
- $[*] ? (@.datetime() < "2015-08-2". datetime())
- 2015-8-1
-
- |
- datetime(template)
- Date/time value converted from a string using the specified template
- ["12:30", "18:40"]
- $[*].datetime("HH24:MI")
- "12:30:00", "18:40:00"
-
- |
- keyvalue()
-
- Sequence of object's key-value pairs represented as array of items
- containing three fields ("key",
- "value", and "id").
- "id" is a unique identifier of the object
- key-value pair belongs to.
-
- {"x": "20", "y": 32}
- $.keyvalue()
- {"key": "x", "value": "20", "id": 0}, {"key": "y", "value": 32, "id": 0}
-
-
-
-
-
-
- The result type of datetime() and
- datetime(template)
- methods can be date, timetz, time,
- timestamptz, or timestamp.
- Both methods determine the result type dynamically.
-
- The datetime() method sequentially tries ISO formats
- for date, timetz, time,
- timestamptz, and timestamp. It stops on
- the first matching format and the corresponding data type.
-
- The datetime(template)
- method determines the result type by the provided template string.
-
- The datetime() and
- datetime(template) methods
- use the same parsing rules as the to_timestamp SQL
- function does (see ), with three
- exceptions. First, these methods don't allow unmatched template
- patterns. Second, only the following separators are allowed in the
- template string: minus sign, period, solidus (slash), comma, apostrophe,
- semicolon, colon and space. Third, separators in the template string
- must exactly match the input string.
-
-
-
-
<type>jsonpath</type> Filter Expression Elements
-
-
- |
- Value/Predicate
- Description
- Example JSON
- Example Query
- Result
-
-
-
- |
- ==
- Equality operator
- [1, 2, 1, 3]
- $[*] ? (@ == 1)
- 1, 1
-
- |
- !=
- Non-equality operator
- [1, 2, 1, 3]
- $[*] ? (@ != 1)
- 2, 3
-
- |
- <>
- Non-equality operator (same as !=)
- [1, 2, 1, 3]
- $[*] ? (@ <> 1)
- 2, 3
-
- |
- <
- Less-than operator
- [1, 2, 3]
- $[*] ? (@ < 2)
- 1
-
- |
- <=
- Less-than-or-equal-to operator
- [1, 2, 3]
- $[*] ? (@ <= 2)
- 1, 2
-
- |
- >
- Greater-than operator
- [1, 2, 3]
- $[*] ? (@ > 2)
- 3
-
- |
- >=
- Greater-than-or-equal-to operator
- [1, 2, 3]
- $[*] ? (@ >= 2)
- 2, 3
-
- |
- true
- Value used to perform comparison with JSON true literal
- [{"name": "John", "parent": false},
- {"name": "Chris", "parent": true}]
- $[*] ? (@.parent == true)
- {"name": "Chris", "parent": true}
-
- |
- false
- Value used to perform comparison with JSON false literal
- [{"name": "John", "parent": false},
- {"name": "Chris", "parent": true}]
- $[*] ? (@.parent == false)
- {"name": "John", "parent": false}
-
- |
- null
- Value used to perform comparison with JSON null value
- [{"name": "Mary", "job": null},
- {"name": "Michael", "job": "driver"}]
- $[*] ? (@.job == null) .name
- "Mary"
-
- |
- &&
- Boolean AND
- [1, 3, 7]
- $[*] ? (@ > 1 && @ < 5)
- 3
-
- |
- ||
- Boolean OR
- [1, 3, 7]
- $[*] ? (@ < 1 || @ > 5)
- 7
-
- |
- !
- Boolean NOT
- [1, 3, 7]
- $[*] ? (!(@ < 5))
- 7
-
- |
- like_regex
-
- Tests whether the first operand matches the regular expression
- given by the second operand, optionally with modifications
- described by a string of flag characters (see
- )
-
- ["abc", "abd", "aBdC", "abdacb", "babc"]
- $[*] ? (@ like_regex "^ab.*c" flag "i")
- "abc", "aBdC", "abdacb"
-
- |
- starts with
- Tests whether the second operand is an initial substring of the first operand
- ["John Smith", "Mary Stone", "Bob Johnson"]
- $[*] ? (@ starts with "John")
- "John Smith"
-
- |
- exists
- Tests whether a path expression matches at least one SQL/JSON item
- {"x": [1, 2], "y": [2, 4]}
- strict $.* ? (exists (@ ? (@[*] > 2)))
- 2, 4
-
- |
- is unknown
- Tests whether a Boolean condition is unknown
- [-1, 2, 7, "infinity"]
- $[*] ? ((@ > 0) is unknown)
- "infinity"
-
-
-
-
-
-
- When different date/time values are compared, an implicit cast is
- applied. A date value can be cast to timestamp
- or timestamptz, timestamp can be cast to
- timestamptz, and time — to timetz.
-
-
The semantics of SQL/JSON path predicates and operators generally follow SQL.
- At the same time, to provide a most natural way of working with JSON data,
- SQL/JSON path syntax uses some of the JavaScript conventions:
+ At the same time, to provide a natural way of working with JSON data,
+ SQL/JSON path syntax uses some JavaScript conventions:
A path expression consists of a sequence of path elements,
- which can be the following:
+ which can be any of the following:
jsonpath operators and methods listed
- in
+ in .
|
$
- A variable representing the JSON text to be queried
+ A variable representing the JSON value being queried
(the context item).
$varname
A named variable. Its value can be set by the parameter
-
vars of several JSON processing functions.
- See and
- its notes for details.
+
vars of several JSON processing functions;
+ see for details.
Member accessor that returns an object member with
- the specified key. If the key name is a named variable
+ the specified key. If the key name matches some named variable
starting with $ or does not meet the
- JavaScript rules of an identifier, it must be enclosed in
- double quotes as a character string literal.
+ JavaScript rules for an identifier, it must be enclosed in
+ double quotes to make it a string literal.
- Same as .**, but with a filter over nesting
- levels of JSON hierarchy. Nesting levels are specified as integers.
- Zero level corresponds to the current object. To access the lowest
+ Like .**, but selects only the specified
+ levels of the JSON hierarchy. Nesting levels are specified as integers.
+ Level zero corresponds to the current object. To access the lowest
nesting level, you can use the last keyword.
This is a
PostgreSQL extension of
the SQL/JSON standard.
The specified index can be an integer, as
well as an expression returning a single numeric value, which is
- automatically cast to integer. Zero index corresponds to the first
+ automatically cast to integer. Index zero corresponds to the first
array element. You can also use the last keyword
to denote the last array element, which is useful for handling arrays
of unknown length.
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