You can use a full outer join to achieve this. Here's an example, assuming OBJECT_ID is the common key

SQL> drop table t1 purge;

Table dropped.

SQL> create table t1 as select object_id, owner, object_name
  2  from dba_objects
  3  where rownum <= 10;

Table created.

SQL>
SQL>
SQL> drop table t2 purge;

Table dropped.

SQL> create table t2 as select object_id, owner, case when rownum = 3 then lower(object_name) else object_name end object_name
  2  from dba_objects
  3  where rownum <= 12;

Table created.

SQL>
SQL>
SQL> select
  2    t1.object_id   t1_obj,
  3    t2.object_id   t2_obj,
  4    t1.owner       t1_own,
  5    t2.owner       t2_own,
  6    t1.object_name t1_name,
  7    t2.object_name t2_name
  8  from t1
  9   full outer join t2
 10  on t1.object_id = t2.object_id
 11  where
 12     t1.object_id is null
 13  or t2.object_id is null
 14  or decode(t1.owner,t2.owner,1,0) = 0
 15  or decode(t1.object_name,t2.object_name,1,0) = 0
 16  ;

    T1_OBJ     T2_OBJ T1_OWN               T2_OWN               T1_NAME                        T2_NAME
---------- ---------- -------------------- -------------------- ------------------------------ ------------------------------
        32         32 SYS                  SYS                  CCOL$                          ccol$
                    6                      SYS                                                 C_TS#
                   48                      SYS                                                 I_COL1

So the three circumstances are catered for:

in T1, not in T2 => t2.obj is null
in T2, not in T1 => t1.obj is null
difference in data => the decode statements

I'm using DECODE because it handles nulls nicely as well, eg, I'll add some data:

SQL> insert into t2 values (-1,'x','y');

1 row created.

SQL> insert into t2 values (-2,'z',null);

1 row created.

SQL> insert into t1 values (-1,'x',null);

1 row created.

SQL> insert into t1 values (-2,'z',null);

1 row created.

So even though there are nulls (and null != null), in this case, we *probably* want to see "-1" because the object_name is differnet, and not see -2, because both are null.

SQL> select
  2    t1.object_id   t1_obj,
  3    t2.object_id   t2_obj,
  4    t1.owner       t1_own,
  5    t2.owner       t2_own,
  6    t1.object_name t1_name,
  7    t2.object_name t2_name
  8  from t1
  9   full outer join t2
 10  on t1.object_id = t2.object_id
 11  where
 12     t1.object_id is null
 13  or t2.object_id is null
 14  or decode(t1.owner,t2.owner,1,0) = 0
 15  or decode(t1.object_name,t2.object_name,1,0) = 0
 16  ;

    T1_OBJ     T2_OBJ T1_OWN               T2_OWN               T1_NAME                        T2_NAME
---------- ---------- -------------------- -------------------- ------------------------------ --------
        32         32 SYS                  SYS                  CCOL$                          ccol$
                    6                      SYS                                                 C_TS#
                   48                      SYS                                                 I_COL1
        -1         -1 x                    x                                                   y

4 rows selected.

You can tailor this into an insert statement or whatever you like.