--
-- SELECT_DISTINCT_ON
--
SELECT DISTINCT ON string4 two, string4, ten
	   FROM tmp
   ORDER BY two using <, string4 using <, ten using <;
 two | string4 | ten 
-----+---------+-----
   0 | AAAAxx  |   0
   0 | HHHHxx  |   0
   0 | OOOOxx  |   0
   0 | VVVVxx  |   0
   1 | AAAAxx  |   1
   1 | HHHHxx  |   1
   1 | OOOOxx  |   1
   1 | VVVVxx  |   1
(8 rows)

