实例讲解一个不用游标就可以实现的问题

1,10
1,11
1,12
2,10
2,13 
数据挖掘研究院
 

10,aaa,1
11,bbb,2
12,ccc,3
13,ddd,4 数据挖掘研究院 

aid,bname,bprice 
数据挖掘研究院
 

1,aaa,1
,bbb,2
,ccc,3
2,aaa,1
,ddd,4 
数据挖掘研究院
 

CREATE TABLE #T1(aid int ,bid int)
INSERT INTO #T1
SELECT 1,10 UNION ALL
SELECT 1,11 UNION ALL
SELECT 1,12 UNION ALL
SELECT 2,10 UNION ALL
SELECT 2,13
CREATE TABLE #T2(bid int,bname nvarchar(10),bprice int)
INSERT INTO #T2
SELECT 10,""aaa"",1 UNION ALL
SELECT 11,""bbb"",2 UNION ALL
SELECT 12,""ccc"",3 UNION ALL
SELECT 13,""ddd"",4
SELECT A.aid,B.bname,B.bprice INTO #T3 FROM #T1 
AS A LEFT OUTER JOIN #T2 AS B ON A.bid=B.bid
DECLARE @aid int ,@lastaid int

UPDATE #T3 SET @aid=(CASE WHEN ISNULL(@lastaid,"""") 
=aid THEN NULL ELSE aid END),aid=@aid,@lastaid=aid
SELECT * FROM #T3
DROP TABLE #T1,#T2,#T3 
数据挖掘研究院
 

/*
1 aaa 1
NULL bbb 2
NULL ccc 3
2 aaa 1
NULL ddd 4
*/ 
数据挖掘研究院