Practical SQL Questions. Exercise 7.

-- 7.1 Who receieved a 1.5kg package? Select Recipient from Package where Weight = 1.5;

SELECT Client.Name FROM Client JOIN Package   
  ON Client.AccountNumber = Package.Recipient WHERE Package.weight = 1.5;

-- The result is "Al Gore's Head".

-- 7.2 What is the total weight of all the packages that he sent?

select sum(weight) from Package where Sender =
(select Recipient from Package where Weight = 1.5);

SELECT SUM(p.weight) FROM Client AS c JOIN Package as P 
  ON c.AccountNumber = p.Sender WHERE c.Name = "Al Gore's Head";