sql遍历字符串语句

declare @ddd   varchar(50),@split varchar(1)

set @ddd = '12345678,1234567890,1234567890,123456,123456789'

set @split = ','
while(charindex(@split,@ddd)<>0)
begin
    select substring(@ddd,1,charindex(@split,@ddd)-1)
    set @ddd = stuff(@ddd,1,charindex(@split,@ddd),'')
    select @ddd
end