mysql> explain SELECT `tags`.* FROM `tags` INNER JOIN `taggings` ON ((`taggings`.`tag_id` = `tags`.`id`) AND (`taggings`.`product_id` = 35))\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: taggings
type: ref
possible_keys: tag_id,product_id
key: product_id
key_len: 5
ref: const
rows: 8
Extra: Using where
*************************** 2. row ***************************
id: 1
select_type: SIMPLE
table: tags
type: eq_ref
possible_keys: PRIMARY
key: PRIMARY
key_len: 4
ref: sandbox.taggings.tag_id
rows: 1
Extra:
2 rows in set (0.00 sec)