Working with Comma Separated Values in SQL

DECLARE @inputstring AS VARCHAR(100),
@ConvertValues AS Varchar(100),
@char1 as varchar(10)
Set @inputstring = '1,2,3,4,5'
SET @ConvertValues=@inputstring
Select @inputstring
WHILE charindex(',', @ConvertValues) > 0
BEGIN
Set @char1 = (SELECT substring(@ConvertValues, 1, ( charindex(',', @ConvertValues) - 1 )))
SET @ConvertValues = substring(@ConvertValues, charindex(',', @ConvertValues) + 1, len(@ConvertValues))
select @char1
select @ConvertValues
END