sqlserver中重复数据值只取一条的sql语句

sqlserver中有时候我们需要获取多条重复数据的一条，需要的朋友可以参考下面的语句

--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 
)