JSON_ARRAYAGG(col_or_expr) [over_clause]

MySQL 8.4

Syntax

MYSQL

SELECT o_id, attribute, value FROM t3;
+------+-----------+-------+
| o_id | attribute | value |
+------+-----------+-------+
|    2 | color     | red   |
|    2 | fabric    | silk  |
|    3 | color     | green |
|    3 | shape     | square|
+------+-----------+-------+
4 rows in set (0.00 sec)

SELECT o_id, JSON_ARRAYAGG(attribute) AS attributes
FROM t3 GROUP BY o_id;
+------+---------------------+
| o_id | attributes          |
+------+---------------------+
|    2 | ["color", "fabric"] |
|    3 | ["color", "shape"]  |
+------+---------------------+
2 rows in set (0.00 sec)

Examples

Example

Aggregates a result set as a single JSON array whose elements consist of the rows. The order of elements in this array is undefined. The function acts on a column or an expression that evaluates to a single value. Returns NULL if the result contains no rows, or in the event of an error. If col_or_expr is NULL, the function returns an array of JSON [null] elements.

MYSQL

SELECT o_id, attribute, value FROM t3;
+------+-----------+-------+
| o_id | attribute | value |
+------+-----------+-------+
|    2 | color     | red   |
|    2 | fabric    | silk  |
|    3 | color     | green |
|    3 | shape     | square|
+------+-----------+-------+
4 rows in set (0.00 sec)

SELECT o_id, JSON_ARRAYAGG(attribute) AS attributes
FROM t3 GROUP BY o_id;
+------+---------------------+
| o_id | attributes          |
+------+---------------------+
|    2 | ["color", "fabric"] |
|    3 | ["color", "shape"]  |
+------+---------------------+
2 rows in set (0.00 sec)