---

SELECT * FROM Authors;
SELECT * FROM Publishing_House;
SELECT * FROM Books;
SELECT * FROM Sales;
GO



2….. DECLARE @a INT;
DECLARE @str VARCHAR(50);

SET @a = (SELECT COUNT(*) FROM Authors);

IF @a > 2
BEGIN
    SET @str = 'Количество авторов больше 2';
END
ELSE
BEGIN
    SET @str = 'Количество авторов = ' + CAST(@a AS VARCHAR(10));
END

SELECT @str;
GO


3….. DECLARE @num INT;
SET @num = 1;

WHILE @num < 10
BEGIN
    PRINT @num;

    IF @num = 5
        BREAK;

    SET @num = @num + 1;
END;
GO


4….. DECLARE @mytable TABLE
(
    id INT,
    myname VARCHAR(20) DEFAULT 'Unknown'
);

INSERT INTO @mytable(id)
VALUES (1);

SELECT * FROM @mytable;
GO



5…. DECLARE @d DATETIME;
DECLARE @str VARCHAR(30);

SET @d = '2025-01-31 13:23:15';
SET @str = CAST(@d AS VARCHAR(30));

SELECT @str;
GO



6…. SET DATEFORMAT dmy;

DECLARE @d DATETIME;
SET @d = '31.01.2025';
SELECT @d;
GO