SQL why wont this let me select a blank value and a value?

Question

I have the following UDF.

CREATE FUNCTION [dbo].[udf_GenerateVarcharTableFromStringList]
        (@list      varchar(MAX),
         @delimiter char(1) = N',')
    RETURNS @tbl TABLE ([Value]     varchar(200)) 
    WITH SCHEMABINDING
    AS
    BEGIN
       DECLARE @chrind INT
       DECLARE @Piece nvarchar(4000)

       SELECT @chrind = 1
       WHILE @chrind > 0
          BEGIN
            SELECT @chrind = CHARINDEX(@delimiter,@list)
             IF @chrind > 0
                SELECT @Piece = LEFT(@list,@chrind - 1)
             ELSE
                SELECT @Piece = @list
             INSERT @tbl([Value]) VALUES(@Piece)
             SELECT @list = RIGHT(@list,LEN(@list) - @chrind)
             IF LEN(@list) = 0 BREAK
          END

       RETURN

    END

I call this function with the following code example from a where clause in my sprocs:

WHERE u.[Owner] IN 
 (SELECT [VALUE] 
  FROM dbo.udf_GenerateVarcharTableFromStringList(@Owners, ','))

I use this where statement in sprocs that I use for reporting services multivalue parameters. When a user selects jsut blank for the value it returns the correct data but if a user selects a blank value and another value that actualyl has text it does not return the blank value owners anymore, just the owners from the text? Any ideas? I take it something is wrong with the function?

Answer 1

Well, from what I could gather from your comments it seems that you need a new splitting function. Here's what I use:

create FUNCTION [dbo].[fnSplitString] (@s varchar(512),@sep char(1))
RETURNS table
AS
RETURN (
    WITH Pieces(pn, start, stop) AS (
      SELECT 1, 1, CHARINDEX(@sep, @s)
      UNION ALL
      SELECT pn + 1, stop + 1, CHARINDEX(@sep, @s, stop + 1)
      FROM Pieces
      WHERE stop > 0
    )
    SELECT pn,
      SUBSTRING(@s, start, CASE WHEN stop > 0 THEN stop-start ELSE 512 END) AS s
    FROM Pieces
  )

It has a nice enumeration feature to it and it doesn't eat blanks. :)