to_json

Converts a semi-structured value to a string containing the JSON representation of the value.

Syntax

to_json( <expr> )

Arguments

<expr>

An expression of semi-structured type (ARRAY, OBJECT, ANY).

Returns

Returns a value of type STRING.

If the input is NULL, the function returns NULL.

Examples

Handling NULL values with TO_JSON:

SELECT to_json(NULL), to_json(parse_json('null'));

+---------------+-----------------------------+
| to_json(NULL) | to_json(parse_json('null')) |
+---------------+-----------------------------+
| null          | null                        |
+---------------+-----------------------------+

Comparing parse_json and TO_JSON:

SELECT to_json(parse_json('{"b":1,"a":2}')) as value,
       to_json(parse_json('{"b":1,"a":2}')) = '{"b":1,"a":2}' as misordered,
       to_json(parse_json('{"b":1,"a":2}')) = '{"a":2,"b":1}' as ordered;

+---------------+------------+---------+
| value         | misordered | ordered |
+---------------+------------+---------+
| {"a":2,"b":1} | false      | true    |
+---------------+------------+---------+