A Database Error Occurred

Error Number: 1055

Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'freegames4rest.games_category.category' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

SELECT `game_id`, `category` FROM (`games_category`) WHERE `game_id` IN ('bricks_of_egypt_2_tears_of_the_pharaohs', 'alice_greenfingers_2', 'bricks_of_atlantis') GROUP BY `game_id`