显示列的分拆的方法

显示列的分拆的方法

create table ta(id int, name varchar(50))
insert ta
select 1, 'aa,bb'
union all select 2, 'aaa,bbb,ccc'
union all select 3, 'Aa,Bb,Cc,Dd'

方法1通过游标实现:

declare @tb table(id int, name varchar(50))--用表变量显示效果
DECLARE @id int,@name varchar(50)
DECLARE roy CURSOR
FOR SELECT * from ta
OPEN roy
FETCH next FROM roy
into @id,@name
WHILE @@FETCH_STATUS = 0
BEGIN
while CHARINDEX(',',@name)>0
begin
INSERT @tb select @id,LEFT(@name,CHARINDEX(',',@name)-1)
SET @name=STUFF(@name,1,CHARINDEX(',',@name),'')
end
insert @tb select @id,@name
FETCH NEXT FROM roy into @id,@name
end
CLOSE roy
DEALLOCATE roy
select * from @tb

方法2用表变量:
declare @ta table(id int)--生成1—50递增的表变量
declare @i int,@j int
select @i=1,@j=50--定义字符的最大数量
while @i!>@j
begin
insert @ta select @i
select @i=@i+1
end
select a.id,
显示列=substring(a.name,b.id,charindex(',',a.name+',',b.id)-b.id)
from ta a,@ta b
where substring(','+a.name,b.id,1)=','

效果如下:

id name
----------- ------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
3 Aa
3 Bb
3 Cc
3 Dd

（所影响的行数为 9 行）

--drop table ta