Outer Join without Outer Join

Question

I'm trying to do is learn how to do an outer join without specifying right, left or full outer join. Why? Performance reasons mostly and to gain a better understanding of Oracle.
Thanks,
Charles.

Answer 1

Another option would be a scalar sub-query in the select portion, like:
SQL> select * from t;
        ID DESCR
         1 T One
         2 T Two
         3 T Three
SQL> select * from t1;
        ID DESCR
         1 T1 One
         2 T1 Two
SQL> select t.*, t1.descr t1_descr
  2  from t
  3     left join t1
  4        on t.id = t1.id;
        ID DESCR      T1_DESCR
         1 T One      T1 One
         2 T Two      T1 Two
         3 T Three
SQL> select t.*, (select t1.descr
  2               from t1
  3               where t.id = t1.id) t1_descr
  4  from t;
        ID DESCR      T1_DESCR
         1 T One      T1 One
         2 T Two      T1 Two
         3 T ThreeThis can be faster if the correlated column in t1 is indexed, and there are a "large" number of records in t that do not match with t1.
John