Draw the initial query tree for each of these queries, then show how the query tree is optimized by the algorithm and write the SQL query for the final optimized query tree.

Q3: List titles of books that are written by author with lastname as Rowling or books available at branch Henry Brentwood.

 SELECT Title FROM Book b, Wrote w, Author a WHERE b.BookCode = w.BookCode and w.AuthorNum = a.AuthorNum and a.AuthorLast = 'Rowling' UNION SELECT Title FROM Book b, Inventory i, Branch r WHERE b.BookCode = i.BookCode and i.BranchNum = r.BranchNum and r.BranchName = 'Henry Brentwood' and i.OnHand > 0;