MariaDB [(none)]> SELECT VERSION();

+------------------------------------------+

| VERSION()                                |

+------------------------------------------+

| 10.3.9-MariaDB-1:10.3.9+maria~bionic-log |

+------------------------------------------+

1 row in set (0.000 sec)

MariaDB [(none)]> SET @`json` := '["A", [{"B": "1"}], {"C": "AB"}, {"D": "BC"}]',

    ->     @`value` := 'AB';

Query OK, 0 rows affected (0.000 sec)

MariaDB [(none)]> SELECT JSON_SEARCH(@`json`, 'one', @`value`);

+---------------------------------------+

| JSON_SEARCH(@`json`, 'one', @`value`) |

+---------------------------------------+

| NULL                                  |

+---------------------------------------+

1 row in set, 1 warning (0.000 sec)

MariaDB [(none)]> SHOW WARNINGS;

+---------+------+---------------------------------------------------------------------------------+

| Level   | Code | Message                                                                         |

+---------+------+---------------------------------------------------------------------------------+

| Warning | 4038 | Syntax error in JSON text in argument 1 to function 'json_search' at position 1 |

+---------+------+---------------------------------------------------------------------------------+

1 row in set (0.000 sec)

MariaDB [(none)]> SELECT JSON_SEARCH(JSON_UNQUOTE(@`json`), 'one', @`value`);

+-----------------------------------------------------+

| JSON_SEARCH(JSON_UNQUOTE(@`json`), 'one', @`value`) |

+-----------------------------------------------------+

| "$[2].C"                                            |

+-----------------------------------------------------+

1 row in set (0.000 sec)

mysql> SELECT VERSION();

+-----------+

| VERSION() |

+-----------+

| 8.0.12    |

+-----------+

1 row in set (0.000 sec)

mysql> SET @`json` := '["A", [{"B": "1"}], {"C": "AB"}, {"D": "BC"}]',

    ->     @`value` := 'AB';

Query OK, 0 rows affected (0.000 sec)

mysql> SELECT JSON_SEARCH(@`json`, 'one', @`value`);

+---------------------------------------+

| JSON_SEARCH(@`json`, 'one', @`value`) |

+---------------------------------------+

| "$[2].C"                              |

+---------------------------------------+

1 row in set (0.000 sec)

mysql> SHOW WARNINGS;

Empty set (0.000 sec)