index 72f223a04145db978df4d0e3c85714f38fbea810..13ccbe7d78c26e947112586da19a1e904b487e95 100644 (file)
<returnvalue>boolean</returnvalue>
</para>
<para>
- 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 <link linkend="functions-sqljson-check-expressions">predicate
check expressions</link>, not SQL-standard JSON path expressions,
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 <type>jsonb</type> result of the
predicate: <literal>true</literal>,
- <literal>false</literal>, or <literal>unknown</literal>.
+ <literal>false</literal>, or <literal>null</literal>.
For example, we could write this SQL-standard filter expression:
<screen>
<prompt>=></prompt> <userinput>select jsonb_path_query(:'json', '$.track.segments ?(@[*].HR > 130)');</userinput>