How to sort by numbers first with Oracle SQL query?

Question

I have this table with a \'title\' field which is varchar2 and I want to select all rows and sort them first by number and then by the alphabet as it normally happens.

Answer 1

the difference in behaviour that you're seeing is probably because of different NLS_SORT parameter setting. Consider:

SQL> select * from nls_session_parameters where parameter='NLS_SORT';

PARAMETER                      VALUE
------------------------------ ----------------------------------------
NLS_SORT                       BINARY

SQL> SELECT * FROM my_data order by title;

TITLE
-----
321
Abc
Def

SQL> alter session set nls_sort=french;

Session altered

SQL> SELECT * FROM my_data order by title;

TITLE
-----
Abc
Def
321

You can build a query that should give you the expected result regardless of your NLS_SORT session parameter setting, for example:

SQL> SELECT *
  2    FROM my_data
  3   ORDER BY CASE
  4               WHEN regexp_like(title, '[0-9]+\.?[0-9]*') THEN
  5                1
  6               ELSE
  7                2
  8            END, title;

TITLE
-----
321
Abc
Def