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  • 用事务实现行转列

    if object_id('Tempdb..#Roy') is not null
    	drop table #Roy
    create table  #Roy (a int,b varchar(10),c int,d int)
    insert #Roy
    select 1,    '小李', 1,    2 union all
    select 2,    '小王', 4,    5  union all 
    select 1,    '小李', 3,    4 union all
    select 2,    '小王', 6,    7 union all
    select 1,    '小李', 5,    6 union all
    select 2,    '小王', 8,    9
    
    
    sql2000实现:
    begin tran 
    	if object_id('tempdb..#roy2') is not null
    		drop table #roy2
    	select a,b,num,id=identity(int,1,1) 
    	into #roy2			--生成临时表
    	from (select a,b,c as num from #Roy
    	union all
    	select a,b,d from #Roy)a order by b,num asc		--排序方式
    
    	--动态查询
    	declare @s nvarchar(1000),@i int
    	select top 1 @i=count(1),@s='' from #roy2 group by a order by count(1) desc
    	while @i>0
    		select @s=',[Col'+rtrim(@i)+']=max(case when ID='+rtrim(@i)+' then rtrim(num) else '''' end)'+@s,@i=@i-1
    	exec('select a,b'+@s+ 'from (select a,b,num,ID=(select count(1) from #roy2 where a=a.a and ID<=a.ID) from #roy2 a)T group by a,b')
    	drop table #roy2
    rollback  tran
    
    sql2005:
    
    begin tran--开始事务
    	declare @i int,@s nvarchar(1000),@Col nvarchar(1000)
    	select 	top 1 @i=count(1),@s='',@Col=''  from #roy unpivot (Num for Col in(c,d))b  group by a order by count(1) desc
    	while @i>0
    		select @s=','+quotename(@i)+@s,@Col=',[Col'+rtrim(@i)+']='+quotename(@i)+@Col,@i=@i-1
    	set @s=stuff(@s,1,1,'')
    
    	exec('with CTE
    	as
    	(select a,b,num,row=row_number()over(partition by a order by num)
    	from 
    		#roy
    	unpivot
    		(Num for Col in(c,d))b)
    	select a,b'+@Col+' from CTE pivot (max(num) for row in('+@s+'))b')
    
    rollback tran
    
    /*
    a           b          Col1        Col2        Col3        Col4        Col5        Col6
    ----------- ---------- ----------- ----------- ----------- ----------- ----------- -----------
    1           小李         1           2           3           4           5           6
    2           小王         4           5           6           7           8           9
    
    (2 行受影响)
    */
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  • 原文地址:https://www.cnblogs.com/Roy_88/p/5463113.html
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