SQL SERVER查询问题(100)

有一表如下:Employeeid Bedid StartDate EndDate 1 1 2010.08.01 2010.09.0110 1 2010.09.10 2010.10.122 3 2010.03.02 2010.05.11155 3 2010.05.05 2010.08.22我想列出每个bedid的最大的startdate的记录.如下:Employeeid Bedid StartDate EndDate10 1 2010.09.10 2010.10.12155 3 2010.05.05 2010.08.22

试试下面的语句（我是Oracle）：Select a.Employeeid, a.Bedid, a.StartDate, a.EndDate From 表 a Left Join (Select Bedid, Max(StartDate) StartDate, Max(EndDate) EndDate From 表 Group By Bedid) b On a.Bedid = b.Bedid and a.StartDate = b.StartDate and a.EndDate = b.EndDate Order By a.Employeeid

Bedid ,startDate 值是不是有可能重复，前面能不能加个自增字段id;select * from test3 where id in (select myid from ( select max(id) as myid , bebid,max(startdate) as b from test3 group by bebid) c )

改为下面的语句试试：Select a.Employeeid, a.Bedid, a.StartDate, a.EndDate From 表 a, (Select Bedid, Max(StartDate) StartDate, Max(EndDate) EndDate From 表 Group By Bedid) b Where a.Bedid = b.Bedid and a.StartDate = b.StartDate and a.EndDate = b.EndDate Order By a.Employeeid;

select Bedid,max(StartDate) from 表 group by Bedid

select * from kk a where StartDate = (select Max(StartDate) from kk where BedId = a.BedId)