1.
CREATE TABLE Ksiazki (
    KsiazkaID INT PRIMARY KEY,
    Tytul VARCHAR(100) NOT NULL,
    Autor VARCHAR(100) NOT NULL,
    RokWydania INT,
    ISBN VARCHAR(20) UNIQUE,
    Cena DECIMAL(10, 2),
    CONSTRAINT CK_RokWydania CHECK (RokWydania >= 0),
    CONSTRAINT CK_Cena CHECK (Cena >= 0)
);
INSERT INTO Ksiazki (KsiazkaID, Tytul, Autor, RokWydania, ISBN, Cena)
VALUES
    (1, 'Harry Potter i Kamień Filozoficzny', 'J.K. Rowling', 1997, '9788372780529', 49.99),
    (2, 'Zabić drozda', 'Harper Lee', 1960, '9788324792491', 29.99),
    (3, 'Wielki Gatsby', 'F. Scott Fitzgerald', 1925, '9788376902858', 39.99);

	select * from Ksiazki

2. 
SELECT *
INTO Customers_new
FROM SalesLT.Customer
WHERE CustomerID IN (
    SELECT DISTINCT CustomerID
    FROM SalesLT.SalesOrderHeader
);

UPDATE Customers_new
SET EmailAddress = CONCAT(EmailAddress, '@example.com')
WHERE SUBSTRING(FirstName, LEN(FirstName), 1) IN ('a', 'b', 'c', 'd', 'e');

DELETE FROM Customers_new
WHERE CustomerID IN (
    SELECT CustomerID
    FROM SalesLT.Customer
    WHERE Title = 'Mr.'
);

select * from Customers_new

3.
CREATE VIEW SalesSummary AS
SELECT P.Name AS ProductName, ISNULL(SUM(SOD.OrderQty), 0) AS QuantitySold, ISNULL(SUM(SOD.LineTotal), 0) AS TotalValue
FROM SalesLT.Product AS P
LEFT JOIN SalesLT.SalesOrderDetail AS SOD ON P.ProductID = SOD.ProductID
WHERE P.ProductID NOT IN (708, 710)
GROUP BY P.Name;


select * from SalesSummary
4.
CREATE PROCEDURE DeleteCustomerAndOperations
  @CustomerID INT
AS
BEGIN
  SET NOCOUNT ON;
  BEGIN TRY
    BEGIN TRANSACTION;
    
    -- Usuwanie operacji klienta
    DELETE FROM SalesLT.SalesOrderDetail
    WHERE SalesOrderID IN (
      SELECT SalesOrderID
      FROM SalesLT.SalesOrderHeader
      WHERE CustomerID = @CustomerID
    );
    
    -- Usuwanie klienta
    DELETE FROM SalesLT.Customer
    WHERE CustomerID = @CustomerID;

    COMMIT;
  END TRY
  BEGIN CATCH
    IF @@TRANCOUNT > 0
    BEGIN
      ROLLBACK;
      SET XACT_ABORT OFF;
    END
    DECLARE @ErrorMessage NVARCHAR(4000);
    SELECT @ErrorMessage = ERROR_MESSAGE();
    RAISERROR(@ErrorMessage, 16, 1);
  END CATCH;
END;

EXEC DeleteCustomerAndOperations @CustomerID = 1;

5.
-- Tworzenie tabeli tymczasowej
SELECT
    Name,
    ProductNumber,
    ListPrice * 2 AS Price,
    Weight
INTO Temp
FROM [SalesLT].[Product]
WHERE Weight IS NOT NULL;

-- Aktualizacja danych w tabeli [SalesLT].[Product] na podstawie tabeli tymczasowej [Temp]
UPDATE P
SET
    P.ListPrice = T.Price,
    P.Weight = T.Weight
FROM [SalesLT].[Product] P
JOIN Temp T ON P.ProductNumber = T.ProductNumber;

-- Usuwanie tabeli tymczasowej
DROP TABLE Temp;