sqlserver中重复数据值只取一条的sql语句

--建立数据表createtable testdata
(
id int identity(1,1) primary key,
data int,
cola varchar(20),
colb varchar(20)
)
go

--插入测试数据
declare @counts int
declare @i int
set @counts = 10000
set @i = 1

while @i<=@counts
begin
insert testdata (data,cola,colb) values(cast(rand()*10000 as int),cast(rand() as varchar(20)),cast(rand() as varchar(20)))
set @i=@i+1
end

--获取数据(重复数据只取一条)
select * from testdata
where
id in
(
--根据data分类获取数据最小id列表
select min(id) from testdata
group by data
)