-
-
-
-SELECT
-
-SQL - Language Statements
-
-
-
-SELECT
-
-
-Retrieve rows from a table or view
-
-
-
-1998-04-15
-
-
-
-
+
+
+
+ SELECT
+
+ SQL - Language Statements
+
+
+
+ SELECT
+
+
+ Retrieve rows from a table or view.
+
+
+
+ 1998-09-06
+
+
SELECT [ALL|DISTINCT]
- expression [AS name] [, ...]
- [INTO [TABLE] intable]
- [FROM table [alias] [, ...] ]
- [WHERE condition]
- [GROUP BY column [, ...] ]
- [HAVING condition [, ...] ]
- [UNION [ALL] select]
- [ORDER BY column [ASC | DESC] [, ...] ]
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-Inputs</div>
<div class="diff rem">-
-
-
-
-
-expression
-
-
- The name of a table's column or an expression.
-
-
-
-
-
-
-name
-
-
- Specifies another name for a column or an expression using
- the AS clause. name cannot be used in the WHERE
- condition. It can, however, be referenced in associated
- ORDER BY or GROUP BY clauses.
-
-
-
-
-
-
-intable
-
-
- If the INTO TABLE clause is specified, the result of the
- query will be stored in another table with the indicated
- name.
-If intable does not exist, it will be created automatically.
-
-
-The CREATE TABLE AS statement will also create a new table from a select query.
-
-
-
-
-
-
-
-
-table
-
-
- The name of an existing table referenced by FROM clause.
-
-
-
-
-
-
-alias
-
-
-An alternate name for the preceeding table.
-Used for brevity or to eliminate ambiguity for joins within a single table.
-
-
-
-
-
-
-condition
-
-
-An expression leading to a boolean (true/false) result.
-See the WHERE clause.
-
-
-
-
-
-
-column
-
-
- The name of a table's column.
-
-
-
-
-
-
-select
-
-
-A select statement with all features except the ORDER BY clause.
-
-
-
-
-
-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-Outputs</div>
<div class="diff rem">-
-
-
-
- Rows
-
-
-The complete set of rows resulting from the query specification.
-
-
-
-
-
-
-count
-
-
-The count of rows returned by the query.
-
-
-
-
-
-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-Description</div>
<div class="diff rem">-
-SELECT is the principal means to access information
-
+ expression [AS name] [, ...]
+ [INTO [TABLE] intable]
+ [FROM table [alias] [, ...] ]
+ [WHERE condition]
+ [GROUP BY column [, ...] ]
+ [HAVING condition [, ...] ]
+ [UNION [ALL] select]
+ [ORDER BY column [ASC | DESC] [, ...] ]
+
+
+
+
+ 1998-09-06
+
+
</div>
<div class="diff add">+ Inputs</div>
<div class="diff add">+
+
+
+
+
+ expression
+
+
+ The name of a table's column or an expression.
+
+
+
+
+
+
+ name
+
+
+ Specifies another name for a column or an expression using
+ the AS clause. name
+ cannot be used in the WHERE
+ condition. It can, however, be referenced in associated
+ ORDER BY or GROUP BY clauses.
+
+
+
+
+
+
+ intable
+
+
+ If the INTO TABLE clause is specified, the result of the
+ query will be stored in another table with the indicated
+ name.
+ If intable does
+ not exist, it will be created automatically.
+
+
+ The CREATE TABLE AS statement will also
+ create a new table from a select query.
+
+
+
+
+
+
+
+
+ table
+
+
+ The name of an existing table referenced by the FROM clause.
+
+
+
+
+
+
+ alias
+
+
+ An alternate name for the preceding
+ table.
+ It is used for brevity or to eliminate ambiguity for joins
+ within a single table.
+
+
+
+
+
+
+ condition
+
+
+ A boolean expression giving a result of true or false.
+ See the WHERE clause.
+
+
+
+
+
+
+ column
+
+
+ The name of a table's column.
+
+
+
+
+
+
+ select
+
+
+ A select statement with all features except the ORDER BY clause.
+
+
+
+
+
+
+
+
+
+
+ 1998-09-06
+
+
</div>
<div class="diff add">+ Outputs</div>
<div class="diff add">+
+
+
+
+ Rows
+
+
+ The complete set of rows resulting from the query specification.
+
+
+
+
+
+
+ count
+
+
+ The count of rows returned by the query.
+
+
+
+
+
+
+
+
+
+
+ 1998-09-06
+
+
</div>
<div class="diff add">+ Description</div>
<div class="diff add">+
SELECT will get all rows which satisfy the WHERE condition
- or all rows of a table if WHERE is omitted.
-
+ or all rows of a table if WHERE is omitted.
+
The GROUP BY clause allows a user to divide a table
- conceptually into groups. (See GROUP BY clause).
-
+ conceptually into groups. (See GROUP BY clause).
+
The HAVING clause specifies a grouped table derived by the
elimination of groups from the result of the previously
- specified clause. (See HAVING clause).
-
+ specified clause. (See HAVING clause).
+
The ORDER BY clause allows a user to specify that he/she
wishes the rows sorted according to the ASCending or
- DESCending mode operator. (See ORDER BY clause)
-
+ DESCending mode operator. (See ORDER BY clause)
+
The UNION clause specifies a table derived from a Cartesian
- product union join. (See UNION clause).
-
+ product union join. (See UNION clause).
+
You must have SELECT privilege to a table to read its values
- (See GRANT/REVOKE statements).
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-WHERE clause</div>
<div class="diff rem">-
- The optional WHERE condition has the general form:
-
-
-WHERE expr cond_op expr [log_op ...]
-
-
- where cond_op can be one of: =, <, <=, >, >=, <>
- or a conditional operator like ALL, ANY, IN, LIKE, et cetera
- and log_op can be one of: AND, OR, NOT.
- The comparison returns either TRUE or FALSE and all
- instances will be discarded
- if the expression evaluates to FALSE.
-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-GROUP BY clause</div>
<div class="diff rem">-
+ (See GRANT/REVOKE statements).
+
+
+
+ 1998-09-06
+
+
</div>
<div class="diff add">+ WHERE clause</div>
<div class="diff add">+
+ The optional WHERE condition has the general form:
+
+
+WHERE expr cond_op expr [log_op ...]
+
+
+ where cond_op can be
+ one of: =, <, <=, >, >=, <>
+ or a conditional operator like ALL, ANY, IN, LIKE, et cetera
+ and log_op can be one
+ of: AND, OR, NOT.
+ The comparison returns either TRUE or FALSE and all
+ instances will be discarded
+ if the expression evaluates to FALSE.
+
+
+
+
+
+ 1998-09-06
+
+
</div>
<div class="diff add">+ GROUP BY clause</div>
<div class="diff add">+
GROUP BY specifies a grouped table derived by the application
of the this clause:
->
-GROUP BY column> [, ...]
->
-
-="R2-SQL-HAVING-2">
->
-1998-04-15>
->
->
-HAVING clause
->
- The optional HAVING condition has the general form:
-
-ynopsis>
-HAVING <REPLACEABLE CLASS="PARAMETER">cond_expr>
-ynopsis>
-
- where cond_expr> is the same
-as specified for the WHERE clause.
-
+ >
+ GROUP BY column> [, ...]
+ >
+
+ ="R2-SQL-HAVING-2">
+ >
+ 1998-09-06>
+ >
+ >
+ HAVING clause
+ >
+ The optional HAVING condition has the general form:
+
+ ynopsis>
+HAVING <replaceable class="PARAMETER">cond_expr>
+ ynopsis>
+
+ where cond_expr> is the same
+ as specified for the WHERE clause.
+
HAVING specifies a grouped table derived by the elimination
of groups from the result of the previously specified clause
- that do not meet the <REPLACEABLE CLASS="PARAMETER">cond_expr.
-
- Each column referenced in <REPLACEABLE CLASS="PARAMETER">cond_expr> shall unambiguously
+ that do not meet the <replaceable class="PARAMETER">cond_expr.
+
+ Each column referenced in <replaceable class="PARAMETER">cond_expr> shall unambiguously
reference a grouping column.
->
-2>
-
-="R2-SQL-ORDERBYCLAUSE-2">
->
-1998-04-15>
->
->
-ORDER BY clause
->
-ynopsis>
-ORDER BY <REPLACEABLE CLASS="PARAMETER">column> [ASC | DESC] [, ...]
->
-
-column> can be either a column
-name or an ordinal number.
+ >
+ 2>
+
+ ="R2-SQL-ORDERBYCLAUSE-2">
+ >
+ 1998-09-06>
+ >
+ >
+ ORDER BY clause
+ >
+ ynopsis>
+ORDER BY <replaceable class="PARAMETER">column> [ASC | DESC] [, ...]
+ >
+
+ column> can be either a column
+ name or an ordinal number.
The ordinal numbers refers to the ordinal (left-to-right) position
of the column. This feature makes it possible to define an ordering
on the basis of a column that does not have a proper name.
This is never absolutely necessary because it is always possible assign a name
to a calculated column using the AS clause, e.g.:
-SELECT title, date_prod + 1 AS newlen FROM films ORDER BY newlen;
->
-
+ SELECT title, date_prod + 1 AS newlen FROM films ORDER BY newlen;
+ >
+
The columns in the ORDER BY must appear in the SELECT clause.
Thus the following statement is illegal:
-SELECT name FROM distributors ORDER BY code;
->
-
+ SELECT name FROM distributors ORDER BY code;
+ >
+
Optionally one may add the keyword DESC (descending)
or ASC (ascending) after each column name in the ORDER BY clause.
- If not specified, ASC is assumed by default.
-2>
-
-="R2-SQL-UNION-2">
->
-1998-04-15>
->
->
-UNION clause
->
-ynopsis>
-<REPLACEABLE CLASS="PARAMETER">table_query UNION [ALL] table_query>
- [ORDER BY column> [ASC | DESC] [, ...] ]
-ynopsis>
-
-where
- table_query>
- specifies any select expression without an ORDER BY clause.
-
- The UNION operator specifies a table derived from a Cartesian product.
- The two tables that represent the direct operands of the UNION must
- have the same number of columns, and corresponding columns must be
- of compatible data types.
-
- By default, the result of UNION does not contain any duplicate rows
- unless the ALL clause is specified.
-
-Multiple UNION operators in the same SELECT statement are evaluated left to right.
-Note that the ALL keyword is not global in nature, being applied only for the current pair of
-table results.
-
->
-
-="R1-SQL-SELECT-2">
->
-Usage
->
-
- --Join table films with their distributors:
- --
+ If not specified, ASC is assumed by default.
+ 2>
+
+ ="R2-SQL-UNION-2">
+ >
+ 1998-09-06>
+ >
+ >
+ UNION clause
+ >
+ ynopsis>
+<replaceable class="PARAMETER">table_query UNION [ALL] table_query>
+ [ORDER BY column> [ASC | DESC] [, ...] ]
+ ynopsis>
+
+ where
+ table_query>
+ specifies any select expression without an ORDER BY clause.
+
+ The UNION operator specifies a table derived from a Cartesian product.
+ The two tables that represent the direct operands of the UNION must
+ have the same number of columns, and corresponding columns must be
+ of compatible data types.
+
+ By default, the result of UNION does not contain any duplicate rows
+ unless the ALL clause is specified.
+
+ Multiple UNION operators in the same SELECT statement are evaluated left to right.
+ Note that the ALL keyword is not global in nature, being applied only for the current pair of
+ table results.
+
+ >
+
+ ="R1-SQL-SELECT-2">
+ >
+ Usage
+ >
+ To join the table films with the table
+ distributors:
+
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d, films f
- WHERE f.did = d.did;
+ WHERE f.did = d.did
title |did|name | date_prod|kind
-------------------------+---+----------------+----------+----------
The King and I |109|20th Century Fox|1956-08-11|Musical
Das Boot |110|Bavaria Atelier |1981-11-11|Drama
Bed Knobs and Broomsticks|111|Walt Disney | |Musical
-
-
- --sum column "len" of all films group by "kind":
- --
+
+ To sum the column len of all films and group
+ the reults by kind:
+
SELECT kind, SUM(len) AS total FROM films GROUP BY kind;
kind |total
Drama | 14:28
Musical | 06:42
Romantic | 04:38
-
-
- --sum column length of all films group by "kind"
- --having total duration < 5 hours:
- --
+
+
+ To sum the column len of all films, group
+ the reults by kind and show those group totals
+ that are less than 5 hours:
+
SELECT kind, SUM(len) AS total
FROM films
GROUP BY kind
----------+------
Comedy | 02:58
Romantic | 04:38
-
-
- --The following two examples are identicals:
- --
+
+ The following two examples are identical ways of sorting the individual
+ results according to the contents of the second column
+ (name):
+
SELECT * FROM distributors ORDER BY name;
SELECT * FROM distributors ORDER BY 2;
111|Walt Disney
112|Warner Bros.
108|Westward
-
-
- --union of table distributors and table actors:
- -- (only those that begin with letter W):
- --
- -- distributors: actors:
+
+
+ This example shows how to obtain the union of the tables
+ distributors and
+ actors, restricting the results to those that begin
+ with letter W in each table. Only distinct rows are to be used, so the
+ ALL keyword is omitted:
+
+ -- distributors: actors:
-- did|name id|name
-- ---+------------ --+--------------
-- 108|Westward 1|Woody Allen
-- 111|Walt Disney 2|Warren Beatty
-- 112|Warner Bros. 3|Walter Matthau
-- ... ...
- --
- --select only distinct rows (without ALL):
- --
+
SELECT distributors.name
FROM distributors
WHERE distributors.name LIKE 'W%'
UNION
SELECT actors.name
FROM actors
- WHERE actors.name LIKE 'W%';
+ WHERE actors.name LIKE 'W%'
name
--------------
Warren Beatty
Westward
Woody Allen
-
-
-
-
-
-
</div>
<div class="diff rem">-Compatibility</div>
<div class="diff rem">-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-<Acronym>SQL92</Acronym></div>
<div class="diff rem">-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-SELECT clause</div>
<div class="diff rem">-
-In the
SQL92 standard, the optional keyword "AS" is just noise and can be
-omitted without affecting the meaning.
-The
Postgres parser requires this keyword when
-renaming columns because the type extensibility features lead to parsing ambiguities
-in this context.
-
-In the
SQL92 standard, the new column name specified in an
-"AS" clause may be referenced in GROUP BY and HAVING clauses. This is not currently
-
-
-
-
-
-1998-04-15
-
-
</div>
<div class="diff rem">-UNION clause</div>
<div class="diff rem">-
-The
SQL92 syntax for UNION allows an additional CORRESPONDING BY clause:
-
-table_query UNION [ALL]
- [CORRESPONDING [BY (column [,...])]]
- table_query
-
-
-The CORRESPONDING BY clause is not supported by
Postgres.
-
-
-
-
-
-
-
-
projects / postgresql.git / commitdiff