Q1:

   
SELECT * 
FROM customers
WHERE country='UK'
ORDER BY contactname;    

Q2:

SELECT * FROM Products
WHERE Price BETWEEN 50 AND 60;

Q3:

SELECT p.productName, p.price, c.categoryName 
FROM categories AS c, products AS p
WHERE c.categoryid = p.categoryid 
AND c.categoryName='Beverages'
AND p.price < 20
ORDER BY p.price DESC;

Q4:

SELECT c.customerid, o.orderid, od.quantity, p.productname 
FROM customers AS c, orders AS o, orderdetails AS od, products AS p
WHERE c.customerid = o.customerid 
AND o.orderid=od.orderid
AND od.productid = p.productid
AND c.customerid = 19;