Help with a sql search query using a comma delimitted parameter

Question

I am looking for something like this but can\'t figure out the best way to write the query:

SELECT DISTINCT CategoryID FROM tbl_Categories c INNER JOIN 
  ma         


        

Answer 1

Create a split function to convert the CSV into a table value, then join the table value function to your select clause to limit the results. See http://phelabaum.com/archive/tag/tally-table/

Quick example (requires you to create a Tally table as detailed over here http://www.sqlservercentral.com/articles/T-SQL/62867/):

CREATE FUNCTION [dbo].[TallySplit] (@Delim CHAR(1), @String VARCHAR(8000))
    RETURNS TABLE AS 
    RETURN (
    SELECT SUBSTRING(@Delim + @String + @Delim,N+1,CHARINDEX(@Delim,@Delim + @String + @Delim,N+1)-N-1) ListValue
    FROM Tally
    WHERE N < LEN(@Delim + @String + @Delim)
    AND SUBSTRING(@Delim + @String + @Delim,N,1) = @Delim 
    )
GO

Then write your select like so:

DECLARE @vCatIDs varchar(max)
SET @vCatIDs = '234,245,645'
SELECT DISTINCT CategoryID FROM tbl_Categories c 
  INNER JOIN mappingTable mp ON c.CategoryID = mp.CategoryID 
  INNER JOIN SubCategories sc ON mp.SubCategoryID = sc.SubCategoryID
  INNER JOIN dbo.TallySplit(',',@vCatIDs) ts ON ts.ListValue = sc.SubCategoryID