id | title | doc_num | version
---+-------+---------+--------
 1 |  bar  |  1234   |   1
 2 |  foo  |  1234   |   2
 3 |  baz  |  5678   |   1

##</code><code>##

SELECT title, doc_num, MAX(version) AS version ORDER BY title;
which produces this:

 title | doc_num | version
-------+---------+--------
  bar  |  1234   |   2
  baz  |  5678   |   1