idselect_typetablepartitionstypepossible_keyskeykey_lenrefrowsfilteredExtra
1SIMPLEtournament_stage_gamesNULLindex_mergefk_tournament_stage_games_tournament_id,fk_tournament_stage_games_use_stage_idfk_tournament_stage_games_tournament_id,fk_tournament_stage_games_use_stage_id5,5NULL1100Using intersect(fk_tournament_stage_games_tournament_id,fk_tournament_stage_games_use_stage_id); Using where