Trace the value in which table

Question

Hi,
i have 3 tables
T1
node_id
T2
node_id, object_type
T3
node_id, object_type
my requirement is T1 node_id exists in which table(T2 or T3). If T1 node_id exists in T2 then return T2 object_type else return T3 object_type
can you please help me to achieve this.
i tried like this
SELECT DECODE (match_flag, 'Match', object_type, NULL)
  FROM (SELECT u1.node_id AS t1_column, u2.node_id AS t2_column,
               CASE
                  WHEN u1.node_id IS NULL OR u2.node_id IS NULL
                     THEN 'No Match'
                  ELSE 'Match'
               END match_flag,
               u2.object_type
          FROM (SELECT node_id
                  FROM t1) u1
               FULL OUTER JOIN
               (SELECT node_id, object_type
                  FROM t2) u2 ON u1.node_id = u2.node_id
WHERE ROWNUM <= 1;

Answer 1

This?
select t1.node_id,nvl(t2.object_type,t3.object_type) object_type
from t1
           left outer join t2
    on (t1.node_id = t2.node_id)
           left outer join t3
    on (t1.node_id = t3.node_id)