sql 去除重复记录的语句
表A：
ID，Name
表B：
ID,AID,Value
select case when a.name='ccc' then null else a.name end name,b.value from 表A a，表B b where a.ID=b.AID
select nullif(a.name,'ccc') name ,b.value from 表A a，表B b where a.ID=b.AID
生成测试数据表: [tb]
IF OBJECT_ID('[tb]') IS NOT NULL
DROP TABLE [tb]
GO
CREATE TABLE [tb] ([name] [nvarchar](10),[value] [int])
INSERT INTO [tb]
SELECT 'aaa','1' UNION ALL
SELECT 'bbb','2' UNION ALL
SELECT 'ccc','3' UNION ALL
SELECT 'ccc','4' UNION ALL
SELECT 'ccc','5'-->SQL查询如下:
SELECT name = CASE [value]
WHEN (
SELECT MIN([value])
FROM tb
WHERE name = t.name
) THEN name
ELSE ''
END, [value]
FROM [tb] t
/*
name value
---------- -----------
aaa 1
bbb 2
ccc 3
4
5
(5 行受影响)