I have this function in Microsoft SQL Server:
CREATE FUNCTION dbo.function_name () RETURNS TABLE AS RETURN ( WITH cte As ( SELECT * FROM TABLE ) SELECT column1, 1 As column_id FROM cte UNION ALL SELECT column2, 2 As column_id FROM cte ) SELECT * FROM dbo.function_name()
After a couple of minutes I still have no output. However if I delete the
UNION ALL part and select only one of those statements it works fine and quick. What do I do wrong?