doc: clarify that jsonb_path_match() returns an SQL boolean

Not a JSON boolean.  Also clarify that other predicate check expressions
functions return a JSON boolean, not an SQL boolean.

Reported-by: jian he
Discussion: https://postgr.es/m/CACJufxH7tP1NXCHN1bUBXcEB=dv7-qE+ZjB3UxwK6Em+9Qzb9Q@mail.gmail.com

Backpatch-through: 17

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 72f223a04145db978df4d0e3c85714f38fbea810..13ccbe7d78c26e947112586da19a1e904b487e95 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -17178,8 +17178,8 @@ ERROR:  value too long for type character(2)
         boolean
        
        
-        Returns the result of a JSON path predicate check for the specified
-        JSON value.
+        Returns the SQL boolean result of a JSON path predicate check
+        for the specified JSON value.
         (This is useful only
         with predicate
         check expressions, not SQL-standard JSON path expressions,
@@ -17646,9 +17646,9 @@ SELECT '{
      Boolean predicate, whereas the SQL standard allows predicates only within
      filters. While SQL-standard path expressions return the relevant
      element(s) of the queried JSON value, predicate check expressions
-     return the single three-valued result of the
+     return the single three-valued jsonb result of the
      predicate: true,
-     false, or unknown.
+     false, or null.
      For example, we could write this SQL-standard filter expression:
 
 => select jsonb_path_query(:'json', '$.track.segments ?(@[*].HR > 130)');