摘要：
先看代码：user 表+-------------+------+----+| name | age | id |+-------------+------+----+| zhangzhibin | 13 | 1 || lisi | 13 | 2 || wangwu | 18 | 3 || zhangzhibin | 19 | 4 || lisi | 12 | 5 || wangwu | 13 | 6 || zhangzhibin | 11 | 7 || lisi | 1... 阅读全文
摘要：
mysql> explain select * from user group by name,age \G*************************** 1. row *************************** id: 1 select_type: SIMPLE table: user type: ALLpossible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 36 Extra: Us... 阅读全文