Question

I have a Stored Procedure that is going to have 3 parameters. I’m wanting to check every combination of Null/Not Null but instead of writing out 16 different Select statements with Else If conditions how else could I write it? Here is my example currently…

...
    ELSE IF @team     IS NOT NULL AND
            @position IS NULL     AND
            @filter   IS NOT NULL

        BEGIN
            SELECT        P1.PlayerKey, P1.Player, P2.Position, P1.Height, P1.Weight, P1.Speed, P1.Status
            FROM          Player AS P1
            INNER JOIN    Position AS P2 ON P1.PositionID = P2.PositionID
            INNER JOIN    Team AS T1 ON T1.TeamID = P1.TeamID
            WHERE         P1.TeamID = @team AND P1.Player LIKE '%' + @filter + '%'
            ORDER BY      P2.PosSort;
        END

    ELSE IF @team     IS NULL     AND
            @position IS NOT NULL AND
            @filter   IS NOT NULL

        BEGIN
            SELECT        P1.PlayerKey, P1.Player, P2.Position, P1.Height, P1.Weight, P1.Speed, P1.Status
            FROM          Player AS P1
            INNER JOIN    Position AS P2 ON P1.PositionID = P2.PositionID
            INNER JOIN    Team AS T1 ON T1.TeamID = P1.TeamID
            WHERE         P2.Position = @position AND P1.Player LIKE '%' + @filter + '%'
            ORDER BY      P2.PosSort;
        END    

    ELSE IF @team     IS NOT NULL AND
            @position IS NULL     AND
            @filter   IS NOT NULL

        BEGIN
            SELECT        P1.PlayerKey, P1.Player, P2.Position, P1.Height, P1.Weight, P1.Speed, P1.Status
            FROM          Player AS P1
            INNER JOIN    Position AS P2 ON P1.PositionID = P2.PositionID
            INNER JOIN    Team AS T1 ON T1.TeamID = P1.TeamID
            WHERE         P1.TeamID = @team AND P1.Player LIKE '%' + @filter + '%'
            ORDER BY      P2.PosSort;
        END
...

Answer 1

SELECT
  P1.PlayerKey, P1.Player, P2.Position, P1.Height, P1.Weight, P1.Speed, P1.Status
FROM Player AS P1
INNER JOIN Position AS P2
  ON P1.PositionID = P2.PositionID
INNER JOIN Team AS T1
  ON T1.TeamID = P1.TeamID
WHERE (@team IS NULL OR P1.TeamID = @team)
AND (@filter IS NULL OR P1.Player LIKE '%' + @filter + '%')
AND (@position IS NULL OR P2.Position = @position)
ORDER BY P2.PosSort;