JSON_OBJECTAGG

Aggregate key-value pairs into a JSON object. This function aggregates two columns or expressions into a single JSON object.

JSON_OBJECTAGG is available from MariaDB 10.5.

Syntax

JSON_OBJECTAGG(key, value)

Description

JSON_OBJECTAGG returns a JSON object containing key-value pairs. It takes two expressions that evaluate to a single value, or two column names, as arguments, the first used as a key, and the second as a value.

The maximum returned length in bytes is determined by the group_concat_max_len server system variable.

Returns NULL in the case of an error, or if the result contains no rows.

JSON_OBJECTAGG cannot currently be used as a window function.

Examples

SELECT * FROM t1;
+------+-------+
| a    | b     |
+------+-------+
|    1 | Hello |
|    1 | World |
|    2 | This  |
+------+-------+

SELECT JSON_OBJECTAGG(a, b) FROM t1;
+----------------------------------------+
| JSON_OBJECTAGG(a, b)                   |
+----------------------------------------+
| {"1":"Hello", "1":"World", "2":"This"} |
+----------------------------------------+

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