Manipulate sqlplus output from a UNION ALL

Question

I have table tA with col a, table tB with col b. Could someone show me how to output the query result like:
a1
b1
a2
b2
a100
b100
not
a1
a2
a100
b1
b2
b100
Thanks.
- Zac

Answer 1

SQL> select * from tA;
                   A
                   1
                   2
                   3
                   4
                   5
                   6
                   7
                   8
                   9
                  10
10 rows selected.
SQL> select * from tB;
                   B
                   1
                   2
                   3
                   4
                   5
                   6
                   7
                   8
                   9
                  10
10 rows selected.
SQL> select 'a', a from tA
  2  union all
  3  select 'b', b from tB
  4  order by 2,1;
'                    A
a                    1
b                    1
a                    2
b                    2
a                    3
b                    3
a                    4
b                    4
a                    5
b                    5
a                    6
b                    6
a                    7
b                    7
a                    8
b                    8
a                    9
b                    9
a                   10
b                   10
20 rows selected.