********************************************************
mysql> explain SELECT
-> m.id_membership, m.code,
-> p.price
-> FROM memberships AS m
-> LEFT JOIN membership_programs AS p ON (p.id_membership = m.id_membership AND p.suspended = 0)
-> WHERE m.id_membership = 2 AND suspended = 0 AND site = "MS"
-> ;
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
| 1 | SIMPLE | m | const | PRIMARY,XAK1_memberships,XAK2_memberships,XFK1_memberships | PRIMARY | 4 | const | 1 | |
| 1 | SIMPLE | p | ref | XFK1_membership_programs,XIE1_membership_programs | XFK1_membership_programs | 4 | const | 2 | Using where |
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
2 rows in set (0.02 sec)
*****************************************************
********* и ПОЧТИ такой же но INNER *******************
*****************************************************
mysql> explain SELECT
-> m.id_membership, m.code,
-> p.price
-> FROM memberships AS m
-> INNER JOIN membership_programs AS p ON (p.id_membership = m.id_membership AND p.suspended = 0)
-> WHERE m.id_membership = 2 AND suspended = 0 AND site = "MS"
-> ;
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
| 1 | SIMPLE | m | const | PRIMARY,XAK1_memberships,XAK2_memberships,XFK1_memberships | PRIMARY | 4 | const | 1 | |
| 1 | SIMPLE | p | ref | XFK1_membership_programs,XIE1_membership_programs | XFK1_membership_programs | 4 | const | 2 | Using where |
+----+-------------+-------+-------+------------------------------------------------------------+--------------------------+---------+-------+------+-------------+
2 rows in set (0.00 sec)
********************************************************
Найдите десять отличий! Или я плохо смотрю?..
Каррроче, експлейн на всю эту фигню что тама что тама выдет для таблицы memberships AS m (которая, обратите ка ваше внимание, стоит в начале произведения) тип связывания CONST. !
Ну это ж никак ни ALL...
