Question

I am creating a stored procedure that sets 3 variables based on queries and I have to return the MAX value of them. I am trying to do so without using a temp table however the following gives me the error Incorrect styntax near ')'

SELECT MAX(PermissionID)
FROM (SELECT @ContactPermission As PermissionID UNION ALL
      SELECT @GroupPermission As PermissionID)

I have also tried

SELECT MAX((SELECT @ContactPermission UNION ALL SELECT @GroupPermission))

and I get the error Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

I have also tried bypassing the variables and using a UNION in a subquery…

SELECT MAX(PermissionID)
FROM (SELECT PermissionID
        FROM PermissionContact
        WHERE ContactID = @ContactID
      UNION ALL
      SELECT PermissionID
      FROM PermissionGroup
      WHERE GroupID = @GroupID)

This also gives the Incorrect syntax near ')'

Any thoughts or suggestions? Are temp tables my only option?

Answer 1

You need to give your derived table an alias.

SELECT MAX(PermissionID)
FROM (SELECT @ContactPermission As PermissionID UNION ALL
      SELECT @GroupPermission As PermissionID) as T