Aggregate functions: SUM

1. SELECT SUM(pages)
2. FROM books;
3.  
4. SELECT SUM(released_year) FROM books;
5.  
6. SELECT author_fname,
7. author_lname,
8. Sum(pages)
9. FROM books
10. GROUP BY
11. author_lname,
12. author_fname;
13.  
14. SELECT author_fname,
15. author_lname,
16. Sum(released_year)
17. FROM books
18. GROUP BY
19. author_lname,
20. author_fname;