SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE ReturnCustomers
@Kundid INT
AS
BEGIN
    WITH Kontaktuppgifter AS
    (
        SELECT K.KundID, K.Namn, K.Ort, T.Telnummer, TP.Teltyp
        FROM Kund AS K
        LEFT JOIN Telefon AS T
        ON K.KundID = T.KundID
        LEFT JOIN Teltyp AS TP
        ON T.TeltypID = TP.TelTypID
    )
        IF @Kundid=0
            BEGIN
            SELECT *
            FROM Kontaktuppgifter
            ORDER BY Namn, Teltyp;
            END
        ELSE
        BEGIN
            SELECT * FROM Kontaktuppgifter
            WHERE Kundid=@Kundid;
            END
END
GO