mysql的join的性能_mysql 子查询与join性能对比

有如下的数据表：

application_daily 11万条数据

application_info400多条数据

查询结果数据为19498

来看下mysql 子查询的例子。

例1，子查询 (0.01s)

复制代码 代码示例:

select sql_no_cache * from application_daily where application_info_id in

(select id from application_info where Team_TeamID=3)

例2，子查询 (0.002s)

复制代码 代码示例:

select sql_no_cache * from application_daily where application_info_id in

(161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190)

例3，连接查询，两条语句等价(0.001s)

复制代码 代码示例:

select sql_no_cache * from application_daily,application_info where

Team_TeamID=3 and application_daily.application_info_id=application_info.id

select sql_no_cache * from application_daily inner join application_info on

(application_daily.application_info_id=application_info.id) where Team_TeamID=3

小结：在子查询时，尽量避免使用in条件。