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| author | Alexander Korotkov <akorotkov@postgresql.org> | 2019-05-17 05:47:53 +0300 |
|---|---|---|
| committer | Alexander Korotkov <akorotkov@postgresql.org> | 2019-05-19 07:43:19 +0300 |
| commit | 87bcc02f4f739d76703feee0ff8346b98fa9b907 (patch) | |
| tree | 631dc5c36b11c0479cf9667926b0cf5d87b77b8e /doc/src | |
| parent | e0e3dad770d3eefc4ee6cd562d9c25b61c263a6e (diff) | |
| download | postgresql-87bcc02f4f739d76703feee0ff8346b98fa9b907.tar.gz postgresql-87bcc02f4f739d76703feee0ff8346b98fa9b907.zip | |
Improve documentation for array subscription in jsonpath
Usage of expressions and multiple ranges in jsonpath array subscription was
undocumented. This commit adds lacking documentation.
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/json.sgml | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml index fae13743984..b8246badda9 100644 --- a/doc/src/sgml/json.sgml +++ b/doc/src/sgml/json.sgml @@ -836,17 +836,22 @@ SELECT jdoc->'guid', jdoc->'name' FROM api WHERE jdoc @> '{"tags": ["qu <para> <literal>[<replaceable>subscript</replaceable>, ...]</literal> </para> - <para> - <literal>[<replaceable>subscript</replaceable> to last]</literal> - </para> </entry> <entry> <para> - Array element accessor. The provided numeric subscripts return the - corresponding array elements. The first element in an array is - accessed with [0]. The <literal>last</literal> keyword denotes - the last subscript in an array and can be used to handle arrays - of unknown length. + Array element accessor. <literal><replaceable>subscript</replaceable></literal> + might be given in two forms: <literal><replaceable>expr</replaceable></literal> + or <literal><replaceable>lower_expr</replaceable> to <replaceable>upper_expr</replaceable></literal>. + The first form specifies single array element by its index. The second + form specified array slice by the range of indexes. Zero index + corresponds to the first array element. + </para> + <para> + Expression inside subscript may consititue an integer, + numeric expression or any other <literal>jsonpath</literal> expression + returning single numeric value. The <literal>last</literal> keyword + can be used in the expression denoting the last subscript in an array. + That's helpful for handling arrays of unknown length. </para> </entry> </row> |