to_json
Description
Converts a Map or Struct value into a JSON string. If the input value is NULL, NULL is returned.
If you want to cast values of other data types, see cast.
This function is supported from v3.1 onwards.
Syntax
to_json(any_value)
Parameters
any_value: the Map or Struct expression you want to convert. If the input value is invalid, an error is returned. The value in each key-value pair of the Map or Struct value is nullable. See the last example.
Return value
Returns a JSON value.
Examples
select to_json(map{1:'a',2:'b'});
+---------------------------+
| to_json(map{1:'a',2:'b'}) |
+---------------------------+
| {"1": "a", "2": "b"} |
+---------------------------+
select to_json(row('asia','eu'));
+--------------------------------+
| to_json(row('asia', 'eu')) |
+--------------------------------+
| {"col1": "asia", "col2": "eu"} |
+--------------------------------+
select to_json(map('a', named_struct('b', 1)));
+----------------------------------------+
| to_json(map{'a':named_struct('b', 1)}) |
+----------------------------------------+
| {"a": {"b": 1}} |
+----------------------------------------+
select to_json(named_struct("k1", cast(null as string), "k2", "v2"));
+-----------------------------------------------------------------------+
| to_json(named_struct('k1', CAST(NULL AS VARCHAR(65533)), 'k2', 'v2')) |
+-----------------------------------------------------------------------+
| {"k1": null, "k2": "v2"} |
+-----------------------------------------------------------------------+