30.05

2.

SELECT c.name, SUM(price * quantity) AS TotalSales
FROM Category c
JOIN Product p ON c.id = p.id_category
WHERE c.name IN ('Мясные', 'Хлебо-булочные')
GROUP BY c.name

3.

SELECT s.name, MIN(d.price * d.quantity) AS Minn
FROM Delivery d
JOIN Supplier s ON s.id = d.id_supplier
WHERE date_of_delivery BETWEEN DATEADD(MONTH, -30, GETDATE()) AND GETDATE()
GROUP BY s.name