id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	plz4	ALL	NULL	NULL	NULL	NULL	5321	Using where; Using temporary; Using filesort
1	SIMPLE	steuern	ref	gemeindeID	gemeindeID	5	cluster.plz4.gemeindeID	1	Using where
1	SIMPLE	gemeinde	eq_ref	PRIMARY	PRIMARY	4	cluster.steuern.gemeindeID	1	Using where
1	SIMPLE	bezirk	eq_ref	PRIMARY	PRIMARY	4	cluster.gemeinde.bezirkID	1	
1	SIMPLE	steuern_kanton	eq_ref	PRIMARY	PRIMARY	4	cluster.bezirk.kantonID	1