Select statement help

[marist89]

SELECT t1.c1, t1.c2, t1.c3, NVL(t2.c4, 'null') c4
  FROM t1
  LEFT OUTER JOIN t2
    ON t1.c1 = t2.c1
   AND t1.c2 = t2.c2;

Is this what your teacher wanted???

LOL!!