Convert JSON array in MySQL to rows

Question

UPDATE: This is now possible in MySQL 8 via the JSON_TABLE function: https://dev.mysql.com/doc/refman/8.0/en/json-table-functions.html

I\'m loving t

Answer 1

1. Create a new table pseudo_rows with values from 0 until 99 - these will be used as keys (if your array has more than a hundred values, add more values into pseudo_rows).

NOTE: If you're running MariaDB, you can skip this and simply use pseudo sequence tables (e.g. seq_0_to_99).

CREATE TABLE `pseudo_rows` (
  `row` int(10) unsigned NOT NULL,
  PRIMARY KEY (`row`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT pseudo_rows VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), (14), (15), (16), (17), (18), (19), (20), (21), (22), (23), (24), (25), (26), (27), (28), (29), (30), (31), (32), (33), (34), (35), (36), (37), (38), (39), (40), (41), (42), (43), (44), (45), (46), (47), (48), (49), (50), (51), (52), (53), (54), (55), (56), (57), (58), (59), (60), (61), (62), (63), (64), (65), (66), (67), (68), (69), (70), (71), (72), (73), (74), (75), (76), (77), (78), (79), (80), (81), (82), (83), (84), (85), (86), (87), (88), (89), (90), (91), (92), (93), (94), (95), (96), (97), (98), (99)

2. For this example, I'll be using a table events which stores groups of artists:

CREATE TABLE `events` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `artists` json DEFAULT NOT NULL,
  PRIMARY KEY (`id`),
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

INSERT INTO `events` (`id`, `artists`) VALUES ('1', '[{\"id\": 123, \"name\": \"Pink Floyd\"}]');
INSERT INTO `events` (`id`, `artists`) VALUES ('2', '[{\"id\": 456, \"name\": \"Nirvana\"}, {\"id\": 789, \"name\": \"Eminem\"}]');

The query to get all artists, one per row, is as follows:

SELECT 
    JSON_UNQUOTE(JSON_EXTRACT(events.artists, CONCAT('$[', pseudo_rows.row, '].name'))) AS performer
FROM events
JOIN pseudo_rows
HAVING performer IS NOT NULL

And the resultset is:

performer
---------
Pink Floyd
Nirvana
Eminem