Airblader commented on a change in pull request #16858:
URL: https://github.com/apache/flink/pull/16858#discussion_r702764140
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File path: docs/data/sql_functions_zh.yml
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@@ -799,6 +798,46 @@ json:
JSON_VALUE('{"a": true}', 'strict $.b'
DEFAULT FALSE ON ERROR)
```
+ - sql: JSON_QUERY(jsonValue, path [ { WITHOUT | WITH CONDITIONAL | WITH
UNCONDITIONAL } [ ARRAY ] WRAPPER ] [ { NULL | EMPTY ARRAY | EMPTY OBJECT |
ERROR } ON EMPTY ] [ { NULL | EMPTY ARRAY | EMPTY OBJECT | ERROR } ON ERROR ])
+ table: STRING.jsonQuery(path [, JsonQueryWrapper [,
JsonQueryOnEmptyOrError, JsonQueryOnEmptyOrError ] ])
+ description: |
+ Extracts JSON values from a JSON string.
+
+ The result is always returned as a `STRING`. The `RETURNING` clause is
currently not supported.
+
+ The `wrappingBehavior` determines whether the extracted value should be
wrapped into an array,
+ and whether to do so unconditionally or only if the value itself isn't
an array already.
+
+ `onEmpty` and `onError` determine the behavior in case the path
expression is empty, or in
+ case an error was raised, respectively. By default, in both cases `null`
is returned. Other
+ choices are to use an empty array, an empty object, or to raise an error.
+
+ ```
+ -- '{ "b": 1 }'
+ JSON_QUERY('{ "a": { "b": 1 } }', '$.a')
+ -- '[1, 2]'
+ JSON_QUERY('[1, 2]', '$')
+
+ -- Wrap result into an array
+ -- '[{}]'
+ JSON_QUERY('{}', '$' WITH CONDITIONAL ARRAY WRAPPER)
Review comment:
The `ARRAY` keyword is optional and only for expresiveness; there is no
difference in behavior either way.
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