MySQL之Explain详解 一.语法explain < table_name >例如: explain select * from t3 where id=3952602;二.explain输出解释+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+| id | select_type | table | type  | possible_keys     | key     | key_len | ref   | rows | Extra |+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+1.id  我的理解是SQL执行的顺利的标识,SQL从大到小的执行.例如:mysql> explain selec

MySQL之Explain详解
一.语法explain < table_name >例如: explain select * from t3 where id=3952602;二.explain输出解释+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+| id | select_type | table | type  | possible_keys     | key     | key_len | ref   | rows | Extra |+----+-------------+-------+-------+-------------------+---------+---------+-------+------+-------+1.id  我的理解是SQL执行的顺利的标识,SQL从大到小的执行.例如:mysql> explain selec