可以选择的去掉重复数据

CREATE TABLE [test] (
 [id] [int] IDENTITY (1, 1) NOT NULL ,
 [a] [varchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
 [b] [varchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
 [c] [varchar] (50) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

INSERT INTO [dbo].[test]([a], [b], [c])VALUES('a','b','c')
INSERT INTO [dbo].[test]([a], [b], [c])VALUES('a','b','cc')
INSERT INTO [dbo].[test]([a], [b], [c])VALUES('aa','bb','c')
INSERT INTO [dbo].[test]([a], [b], [c])VALUES('aa','bb','cc')
INSERT INTO [dbo].[test]([a], [b], [c])VALUES('a','bb','ccc')

--查询语句
select id,a,b,c from test a where
id=(SELECT min(id) FROM test b where a.a =b.a and a.b=b.b) order by id
--drop table [test]