同一字段重复的数据只取一条

--如果相同取 NAME 最大的一条
 
create table #(id int identity(1,1),attachid int,name varchar(10))
 
insert into # values(23,'sss')
insert into # values(33,'sdfs')
insert into # values(33,'4434')
insert into # values(45,'dsdsd')
 
select * from #  a where not exists (select 1 from # where attachid=a.attachid and name<a.name)
 
 
 
id          attachid    name
----------- ----------- ----------
1           23          sss
3           33          4434
4           45          dsdsd
 
(3 行受影响)