Question

I am trying to figure out how to inner join a table that has ID’s to my table that have all the ids in one row separated by commas.

The table with the commas is called (PA):

usersIDs
56488,51233,71055,98304,21577,12500

The table (SU) has the id and the name of the user:

UserID | Name
51233  | Bob Barker
21577  | Billy Knox
56488  | David Miller
etc etc

How can I inner join the name with the comma separated ID’s in my first table?

 SELECT DISTINCT SU.Name, SU.UserID, SU.Enabled
 FROM Sec_User AS SU INNER JOIN
    Program_Access AS PA ON SU.UserId = PA.userIDS

Answer 1

Here’s a way without a function:

SELECT DISTINCT SU.UserID, SU.Name, SU.Enabled
 FROM dbo.Sec_User AS SU
 INNER JOIN dbo.Program_Access AS PA
 ON ',' + PA.usersIDs + ',' LIKE '%,' + RTRIM(SU.UserID) + ',%';

But including the function for completeness (and because having such a function is very useful for many purposes). First create a table-valued function:

CREATE FUNCTION dbo.SplitInts
(
   @List       VARCHAR(MAX),
   @Delimiter  CHAR(1)
)
RETURNS TABLE
AS
   RETURN ( SELECT Item = CONVERT(INT, Item) FROM ( 
     SELECT Item = x.i.value('(./text())[1]', 'int') FROM ( 
       SELECT [XML] = CONVERT(XML, '<i>' + REPLACE(@List, @Delimiter, '</i><i>') 
       + '</i>').query('.') ) AS a CROSS APPLY [XML].nodes('i') AS x(i)) AS y
     WHERE Item IS NOT NULL
   );

Now the JOIN:

 SELECT DISTINCT SU.UserID, SU.Name, SU.Enabled
  FROM dbo.Program_Access AS PA 
  CROSS APPLY dbo.SplitInts(PA.usersIDs, ',') AS s
  INNER JOIN dbo.Sec_User AS SU
  ON SU.UserID = s.Item;