Oracle:Jeg har brug for en delvis ydre joinforbindelse. Se på billedet

Bare lav en ydre sammenføjning, men brug også sammensmeltning

SELECT
   COALESCE(a.master,b.master) master,
   a.ColA,
   b.ColB
FROM
  a FULL OUTER JOIN B
  ON a.master = b.master
     AND (a.ColA = b.ColB 
          or a.ColA is Null
          or b.ColB is Null)
ORDER BY 
    COALESCE(a.master,b.master),
    COALESCE(a.cola,b.colB)

Se det fungere her