text: /* 1 */
  
  SELECT Books.book_title, Authors.first_name,Authors.last_name
  FROM  Authors JOIN Books
  WHERE Authors.author_id = Books.Editor;
  
  /* 2 */
  
  SELECT B.book_title, A.first_name,A.last_name
  FROM  Authors as A 
  	JOIN (
  		SELECT Books.book_title, Authorship.Author_id
  		FROM Books JOIN Authorship
          WHERE Books.book_id = Authorship.book_id ) AS B
  WHERE A.author_id = B.author_id;
      
  /* 3 */
  
  SELECT Pizzeria.name, Person.name
  FROM Pizzeria JOIN Person
  ON Pizzeria.city = Person.City;
  
  /* 4 */
  
  SELECT Person.Name 
  FROM Person JOIN (
    SELECT MIN(age) as 'min'
    FROM Person
  ) AS MINAGE
  WHERE Person.Age = MINAGE.min;
  
  /* 5 */
  
  SELECT Name
  From Pizzeria JOIN
  	(SELECT Pizzeria
      FROM Frequents JOIN Person
      ON Frequents.Name = Person.Name
      WHERE Person.Age < 18) AS F
      Where Pizzeria.Name = F.Pizzeria;
      
      
  /* 6 */
  SELECT country.Name, SUM(city.Population)
  FROM country JOIN city
  ON country.Code = city.CountryCode
  GROUP BY country.code
  ORDER BY SUM(city.population) DESC;
  
  
  /* 7 */
  SELECT country.name, countrylanguage.Language
  FROM country join countrylanguage
  ON country.Code = countrylanguage.CountryCode
  WHERE countrylanguage.IsOfficial = TRUE;
  
  /* 8 */
  
  SELECT country.Name, city.name, city.district
  FROM city JOIN country
  ON city.CountryCode = country.Code AND
     city.ID = country.Capital;
  
  
  /* 9 */
  
  SELECT A.district, B.language
  FROM (
    SELECT city.district, country.Code
    FROM city JOIN country
    ON city.CountryCode = country.Code AND
       city.ID = country.Capital
    ) AS A
    JOIN (
  	SELECT country.Code, countrylanguage.Language
  	FROM country join countrylanguage
  	ON country.Code = countrylanguage.CountryCode
  	WHERE countrylanguage.IsOfficial = TRUE
      ) AS B
  where A.Code = B.Code;
   
  