Exercise #23 page 3

Console

Execute

SELECT maker, a.model a_m, b.model b_m, c.model c_m
FROM Product a, PC b, Laptop c 
WHERE ((b.speed >= 750 AND 
        c.speed >= 750
        ) AND 
        a.model = b.model
       ) OR 
       ((b.speed >= 750 AND 
         c.speed >= 750
        ) AND 
         a.model = c.model
       );

SELECT maker, a.model a_m, b.model b_m, c.model c_m FROM Product a, PC b, Laptop c WHERE ((b.speed >= 750 AND         c.speed >= 750         ) AND         a.model = b.model        ) OR        ((b.speed >= 750 AND          c.speed >= 750         ) AND          a.model = c.model        );

    Scheme

Console

Execute

SELECT maker
FROM (SELECT maker 
      FROM Product INNER JOIN 
           PC ON Product.model = PC.model 
      WHERE type='PC' AND 
            speed >= 750
      UNION ALL
      SELECT maker 
      FROM Product INNER JOIN 
            Laptop ON Product.model = Laptop.model
      WHERE type='laptop' AND 
            speed >= 750
      ) S
GROUP BY maker;

SELECT maker FROM (SELECT maker       FROM Product INNER JOIN            PC ON Product.model = PC.model       WHERE type='PC' AND             speed >= 750       UNION ALL       SELECT maker       FROM Product INNER JOIN             Laptop ON Product.model = Laptop.model       WHERE type='laptop' AND             speed >= 750       ) S GROUP BY maker;

    Scheme

Console

Execute

SELECT maker
FROM Product
WHERE model IN (SELECT model 
                FROM PC 
                WHERE speed >= 750 
                UNION ALL
                SELECT model 
                FROM Laptop 
                WHERE speed >= 750
                )
GROUP BY maker;

SELECT maker FROM Product WHERE model IN (SELECT model                 FROM PC                 WHERE speed >= 750                 UNION ALL                 SELECT model                 FROM Laptop                 WHERE speed >= 750                 ) GROUP BY maker;

    Scheme