• 类似于行转列的一种需求


    在 工作中 遇到这样一种需求:

    在群里问了下朋友,朋友 SQL 代码如下:

    create table dou
    (
    number nvarchar(10),
    no int,
    name nvarchar(10),
    height int
    )
     
    
    insert into dou
    select 'AAA',1,'张三',120
    union all select 'AAA',1,'李四', 115
    union all select 'AAA',2,'王五', 112
    union all select 'AAA',3,'赵六', 125
    union all select 'AAA',3,'周八', 132
    union all select 'AAA',3,'刘九', 136
    union all select 'AAA',3,'草根', 136
    union all select 'BBB',1,'B第一', 132
    union all select 'BBB',2,'B第二', 136
    union all select 'CCC',1,'C第一', 136
    go
    
    --SELECT * FROM dou
    
    if object_id('tempdb..#t') is not null Begin  
    drop table #t  
    End 
    
    create table #t (row int, number nvarchar(10))
    
    --
    declare @maxrow int
    set @maxrow = 0
    select @maxrow = max(no) from dou
    
    declare @i int
    set @i =1 
    declare @tempsql nvarchar(max)
    while @i <= @maxrow
    begin
        set @tempsql = 'alter table #t add no'+cast(@i as nvarchar(10))+' int;'
        set @tempsql = @tempsql + 'alter table #t add name'+cast(@i as nvarchar(10))+' nvarchar(10);'
        set @tempsql = @tempsql + 'alter table #t add height'+cast(@i as nvarchar(10))+' int;'
        exec(@tempsql)
        set @i = @i +1
    end
    
    --
    declare @maxcol int
    set @maxcol = 0
    select @maxcol = max(couno) from (select no,count(no) couno from dou group by no ) a
    
    declare @sqlinsone nvarchar(max)
    set @sqlinsone ='insert into #t (row,number,no'+cast(@maxrow as varchar)+',name'+cast(@maxrow as varchar)+',height'+cast(@maxrow as varchar)+') select row_number() over (order by getdate()),number,no,name,height from dou where no =' + cast(@maxrow as varchar)
    exec(@sqlinsone)
    
    set @i =1 
    while @i <= @maxrow
    begin
        set @sqlinsone = 'update a set no'+cast(@i as varchar)+' = no,name'+cast(@i as varchar)+' =name,height'+cast(@i as varchar)+' = height from #t a inner join (select * ,row_number() over (order by getdate()) row from dou where no = '+cast(@i as varchar)+') b on a.number = b.number and a.row = b.row'
        exec(@sqlinsone)
        set @i = @i +1
    end
    
    select * from #t
    drop table #t

    结果如下,但只显示 AAA 的,BBB的没有显示(在WHERE 条件中 限制了 NUBLER 的条件 ,一次只查一个内容):

    create table dou
    (
    number nvarchar(10),
    no int,
    name nvarchar(10),
    height int
    )
    go
    
    insert into dou
    select 'AAA',1,'张三',120
    union all select 'AAA',1,'李四', 115
    union all select 'AAA',2,'王五', 112
    union all select 'AAA',3,'赵六', 125
    union all select 'AAA',3,'周八', 132
    union all select 'AAA',3,'刘九', 136
    union all select 'AAA',3,'草根', 136
    union all select 'BBB',1,'草根1', 136
    union all select 'BBB',2,'草根2', 136
    union all select 'BBB',3,'草根3', 136
    union all select 'BBB',2,'草根4', 136
    union all select 'CCC',1,'草根5', 136
    union all select 'CCC',2,'草根6', 136
    go
    
    if object_id('tempdb..#t') is not null Begin  
    drop table #t  
    End 
    
    create table #t (row int, number nvarchar(10))
    
    -- 列
    declare @maxrow int
    set @maxrow = 0
    select @maxrow = max(no) from dou
    
    declare @i int
    set @i =1 
    declare @tempsql nvarchar(max)
    while @i <= @maxrow
    begin
    	set @tempsql = 'alter table #t add no'+cast(@i as nvarchar(10))+' int;'
    	set @tempsql = @tempsql + 'alter table #t add name'+cast(@i as nvarchar(10))+' nvarchar(10);'
    	set @tempsql = @tempsql + 'alter table #t add height'+cast(@i as nvarchar(10))+' int;'
    	exec(@tempsql)
    	set @i = @i +1
    end
    
    -- 一共几种类型
    declare @type int
    declare @number nvarchar(10)
    select @type = count(*) from ( select number from dou group by number) a
    declare @j int
    set @j = 1
    while @j <= @type
    begin 
    	;with cte as
    	(
    		select number,max(no) no,row_number() over (order by getdate()) row from dou group by number
    	)
    	select @maxrow = no,@number = number from cte where row = @j
    
    	-- 行
    	declare @maxcol int
    	set @maxcol = 0
    	select @maxcol =max(no) from dou where number = 'BBB' 
    
    	declare @sqlinsone nvarchar(max)
    	set @sqlinsone ='insert into #t (row,number,no'+cast(@maxrow as varchar)+',name'+cast(@maxrow as varchar)+',height'+cast(@maxrow as varchar)+') select row_number() over (order by getdate()),number,no,name,height from dou where no =' + cast(@maxrow as varchar) + ' and number = ''' + @number + ''''
    	exec(@sqlinsone)
    
    	set @i =1 
    	while @i <= @maxrow
    	begin
    		set @sqlinsone = 'update a set no'+cast(@i as varchar)+' = no,name'+cast(@i as varchar)+' =name,height'+cast(@i as varchar)+' = height from #t a inner join (select * ,row_number() over (order by getdate()) row from dou where no = '+cast(@i as varchar)+' and number = '''+@number+''') b on a.number = b.number and a.row = b.row where b.number = ''' + @number + ''''
    		exec(@sqlinsone)
    		set @i = @i +1
    	end
    
    	set @j = @j + 1
    end
    
    select * from #t
    drop table #t
    

      这是第二种,显示如下: 

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  • 原文地址:https://www.cnblogs.com/cgdou/p/2730836.html
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