text: -- Ex.1 Find Book Titles
  SELECT title FROM books
  WHERE LEFT(title, 3) = 'The'
  ORDER BY id;
  
  -- Ex.2 Replace Titles
  UPDATE books
  SET title = REPLACE(title, 'The', '***')
  WHERE LEFT(title, 3) = 'The';
  
  
  SELECT title FROM books 
  WHERE LEFT(title, 3) = '***'
  ORDER BY id;
  
  -- Ex.3 Sum Cost of All Books
  SELECT ROUND(SUM(cost), 2) FROM books;
  
  -- Ex.4 Days Lived
  SELECT CONCAT(first_name, ' ', last_name) AS 'Full Name',
  TIMESTAMPDIFF(DAY, born, died) AS 'Days Lived' FROM authors;
  
  -- Ex.5 Harry Potter Books
  SELECT title FROM books
  WHERE title LIKE 'Harry Potter%'
  ORDER BY id;