Question

You can return a single table from a T-SQL Function in SQL Server 2008.

I am wondering if it is possible to return more than one table.

The scenario is that I have three queries that filter 3 different tables. Each table is filtered against 5 filter tables that I would like to return from a function; rather than copy and paste their creation in each query.

An simplified example of what this would look like with copy and paste:

FUNCTION GetValuesA(@SomeParameter int) RETURNS @ids TABLE (ID int) AS 

  WITH Filter1 As ( Select id FROM FilterTable1 WHERE Attribute=SomeParameter )
     , Filter2 As ( Select id FROM FilterTable2 WHERE Attribute=SomeParameter )

  INSERT INTO @IDs
  SELECT ID FROM ValueTableA
  WHERE ColA IN (SELECT id FROM Filter1)
  AND   ColB IN (SELECT id FROM Filter2)

  RETURN

-----------------------------------------------------------------------------

FUNCTION GetValuesB(@SomeParameter int) RETURNS @ids TABLE (ID int) AS 

  WITH Filter1 As ( Select id FROM FilterTable1 WHERE Attribute=SomeParameter )
     , Filter2 As ( Select id FROM FilterTable2 WHERE Attribute=SomeParameter )

  INSERT INTO @IDs
  SELECT ID FROM ValueTableB
  WHERE ColA IN (SELECT id FROM Filter1)
  AND   ColB IN (SELECT id FROM Filter2)
  AND   ColC IN (SELECT id FROM Filter2)

  RETURN

So, the only difference between the two queries is the Table being filtered, and HOW (the Where clause).

I would like to know if I could return Filter1 & Filter2 from a function. I am also open to suggestions on different ways to approach this problem.

Answer 1

No.

Conceptually, how would you expect to handle a function that returned a variable number of tables? You would JOIN on two tables at once? What if the returned fields don’t line up?

Is there some reason you can’t have a TVF for each filter?