如何把字符串分割成数组

[lgh860121]

假如： declare @ids varchar(20)
    set @ids='1,2,3'

怎么实现
select * from a where id in('1','2','3')这种效果

[lgh860121]

忘了说 可以不要
exec @sql 这种方式吗

[打一壶酱油]

declare @ids varchar(20)
set @ids='1,2,3'

select * from a where charindex(','+cast(id as varchar(10))+',',','+ @ids+',') > 0

[lgh860121]

强！很好啊