sql获取分组后取某字段最大一条记录

获取分组后取某字段最大一条记录 方法一：(效率最高)

select * from test as a  
where typeindex = (select max(b.typeindex)  
from test as b  
where a.type = b.type );  

方法二：(效率次之)

select  
a.* from test a,  
(select type,max(typeindex) typeindex from test group by type) b  
where a.type = b.type and a.typeindex = b.typeindex order by a.type