mysql分组获取时间最大的记录
![](https://img2018.cnblogs.com/blog/1465988/201811/1465988-20181114175533779-1430638857.png)
要求:获得按table1_id分组,并且age最大的记录信息,即2、3、5条
方法一:
select * from (select * from table2 order by age desc) as a group by a.table1_id
方法二:
select a.* from table2 as a where age = (select max(age) from table2 where a.table1_id=table1_id)
方法三:
select a.* from table2 as a where not exists (select * from table2 where table1_id=a.table1_id and age>a.age)
方法四:
select a.* from table2 as a where exists (select count(*) from table2 where table1_id=a.table1_id and age>a.age having count(*)=0)