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 ('lost_inca_prophecy_2_the_hollow_island', 'hello_venice', 'wild_west_story_the_beginning', 'the_lost_kingdom_prophecy', 'the_lost_inca_prophecy', 'fairy_island') GROUP BY `game_id`