sqlserver中遍历字符串的sql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