id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	db2_alertdoc	NULL	ref	fk_db2_alertdoc_db2_bollettario1_idx	fk_db2_alertdoc_db2_bollettario1_idx	8	const	1	100.00	Using index condition