-- ================================================
-- Template generated from Template Explorer using:
-- Create Procedure (New Menu).SQL
--
-- Use the Specify Values for Template Parameters
-- command (Ctrl-Shift-M) to fill in the parameter
-- values below.
--
-- This block of comments will not be included in
-- the definition of the procedure.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:		<Author,,Name>
-- Create date: <Create Date,,>
-- Description:	<Description,,>
-- =============================================
CREATE PROCEDURE [dbo].[Lab1Zad4]
	-- Add the parameters for the stored procedure here
	@kolumna AS sysname = NULL,
	@porzadek AS CHAR = 'A'
AS
BEGIN

	DECLARE @msg AS NVARCHAR(100)

	-- jezeli nie podano nazwy kolumny
	IF @kolumna iS NULL
	BEGIN
		SET @msg = 'PARAMETR @kolumna NIE MOŻE BYĆ PUSTEJ (NULL)'
		PRINT @msg
		RETURN
	END

	-- czy kolumna nalezy do zbioru
	IF @kolumna NOT IN ('ShipperID', 'CompanyName', 'Phone')
	BEGIN
		SET @msg = 'PARAMETR @kolumna NIE MOŻE BYĆ PUSTEJ (NULL)'
		PRINT @msg
		RETURN
	END

	SELECT ShipperID, CompanyName, Phone FROM Shippers
		ORDER BY CASE WHEN @kolumna = 'ShipperID' AND @porzadek = 'A' THEN ShipperID END ASC,
		CASE WHEN @kolumna = 'ShipperID' AND @porzadek = 'D' THEN ShipperID END DESC,
		CASE WHEN @kolumna = 'CompanyName' AND @porzadek = 'A' THEN CompanyName END ASC,
		CASE WHEN @kolumna = 'CompanyName' AND @porzadek = 'D' THEN CompanyName END DESC,
		CASE WHEN @kolumna = 'Phone' AND @porzadek = 'A' THEN Phone END ASC,
		CASE WHEN @kolumna = 'Phone' AND @porzadek = 'D' THEN Phone END DESC

END
GO