id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	PRIMARY	tournaments	NULL	index	fk_tournaments_age_category_id	fk_tournaments_age_category_id	5	NULL	67	10.45	Using where; Using index; Using temporary; Using filesort; LooseScan
1	PRIMARY	age_category	NULL	eq_ref	PRIMARY	PRIMARY	4	playtennis_dev.tournaments.age_category_id	1	100	NULL
7	SUBQUERY	tournament_has_players_double	NULL	ALL	PRIMARY	NULL	NULL	NULL	4	33.33	Using where
6	DEPENDENT SUBQUERY	tournaments_has_profiles	NULL	index_subquery	PRIMARY	PRIMARY	4	func	7	33.33	Using where
4	SUBQUERY	players_double	NULL	index_merge	PRIMARY,fk_players_double_player_1_id,fk_players_double_player_2_id	fk_players_double_player_1_id,fk_players_double_player_2_id	4,4	NULL	2	100	Using union(fk_players_double_player_1_id,fk_players_double_player_2_id); Using where
4	SUBQUERY	tournament_has_players_double	NULL	ref	PRIMARY,fk_tournament_has_players_double_players_double_id	fk_tournament_has_players_double_players_double_id	4	playtennis_dev.players_double.id	1	100	Using index
3	SUBQUERY	tournaments_has_profiles	NULL	ref	PRIMARY,fk_tournaments_has_profiles_profile_id	fk_tournaments_has_profiles_profile_id	4	const	1	100	Using index