Rewrite the query with out joins and group by

Question

Hi,
This was an interview question.
Table Names: bookshelf_checkout
bookshelf
And the join condition between these two tables is title
We need to rewrite below query without using join condition and group by clause ?
SELECT b.title,max(bc.returned_date - bc.checkout_date) "Most Days Out"
           FROM bookshelf_checkout bc,bookshelf b
           WHERE bc.title(+)=b.title
           GROUP BY b.title;When I was in college, I read that most of the SELECT statements can be replaced by basic SQL operations (SET OPERATORS). Now I am trying to rewrite the query with SET operators but not able to get the exact result.
Kindly help me on this.
Thanks,
Suri

Answer 1

Something like this?
  1  WITH books AS (
  2  SELECT 'title 1' title FROM dual UNION ALL
  3  SELECT 'title 2' FROM dual UNION ALL
  4  SELECT 'title 3' FROM dual ),
  5  bookshelf AS (
  6  SELECT 'title 1' title, DATE '2012-05-01' checkout_date, DATE '2012-05-15' returned_date FROM dual UNION ALL
  7  SELECT 'title 1' title, DATE '2012-05-16' checkout_date, DATE '2012-05-20' returned_date FROM dual UNION ALL
  8  SELECT 'title 2' title, DATE '2012-04-01' checkout_date, DATE '2012-05-15' returned_date FROM dual )
  9  SELECT bs.title, MAX(bs.returned_date - bs.checkout_date) OVER (PARTITION BY title) FROM bookshelf bs
10  UNION
11  (SELECT b.title, NULL FROM books b
12  MINUS
13* SELECT bs.title, NULL FROM bookshelf bs)
SQL> /
TITLE   MAX(BS.RETURNED_DATE-BS.CHECKOUT_DATE)OVER(PARTITIONBYTITLE)
title 1                                                           14
title 2                                                           44
title 3Lukasz