USE Ships;
-- 1
SELECT Class, country
FROM Classes
WHERE (bore >= 16);

-- 2
SELECT name
FROM Ships
WHERE (launched <= 1921);

-- 3
SELECT ship
FROM Outcomes
WHERE result = 'sunk'
  AND battle = 'North Atlantic';

-- 4
SELECT name
FROM Ships
WHERE launched >= 1922
  AND class IN (SELECT class
                FROM Classes
                WHERE displacement > 35000);

-- 5
SELECT Ships.class, name, country
FROM Ships,
     Classes
WHERE Ships.class IN (SELECT class FROM Classes WHERE numGuns > 10);

-- 6
SELECT name
FROM Ships
WHERE launched < 1941;

-- 7
SELECT ship, battle
FROM Outcomes
WHERE result = 'sunk';

-- 8
SELECT country, MAX(numGuns)
FROM Classes
GROUP BY country;

-- 9
SELECT DISTINCT battle
FROM Outcomes
WHERE ship IN (SELECT name FROM Ships WHERE class = 'Kongo')

-- 10
SELECT name
FROM Ships
WHERE name LIKE 'R%'

-- 11
SELECT name
FROM ships
WHERE name LIKE '% % %'

-- 12
SELECT COUNT(*)
FROM Classes
WHERE type = 'bb'

-- 13
SELECT C.class, MIN(launched)
FROM Ships AS S
         RIGHT JOIN Classes AS C ON S.class = C.class
GROUP BY C.class

-- 14

SELECT round(avg(numGuns), 2)
FROM classes
WHERE type = 'bb';
USE ComputerCompany;

-- 15
SELECT model, speed, ram, hd
FROM PC
WHERE (price < 500)

--16
SELECT maker
FROM Product
WHERE type = 'Printer'
GROUP BY maker

--17
SELECT model, speed, ram
FROM Laptop
WHERE (price > 1000)

--18
SELECT *
FROM Printer
WHERE color = 'y'

--19
SELECT model, speed, hd
FROM PC
WHERE cd IN ('24x', '12x')
  AND price < 600

--20
SELECT DISTINCT Product.maker, Laptop.speed
FROM Product,
     Laptop
WHERE Laptop.hd >= 10
  AND type IN (SELECT type
               FROM Product
               WHERE type = 'laptop'
);

--21
SELECT DISTINCT Product.maker, Laptop.speed
FROM Product,
     Laptop
WHERE Laptop.hd >= 10
  AND type IN (SELECT type
               FROM Product
               WHERE type = 'laptop'
);

--22
SELECT DISTINCT product.maker
FROM pc
         INNER JOIN product ON pc.model = product.model
WHERE pc.speed >= 450

--23
SELECT model, price
FROM printer
WHERE price = (SELECT MAX(price) FROM printer)

--24
SELECT AVG(speed) AS AVERAGE_SPEED
FROM PC

--25
SELECT AVG(speed) AS AVERAGE_SPEED
FROM Laptop
WHERE (price > 1000)

--26
SELECT AVG(pc.speed)
FROM pc,
     product
WHERE pc.model = product.model
  AND product.maker = 'A'

--27
SELECT pc.speed, AVG(pc.price)
FROM pc
GROUP BY pc.speed