How do I store phone numbers in PostgreSQL?
libphonenumber

When possible always use the canonical form. The more normalized the form the better. If there is a standard, use it. For this problem, let's use Google's libphonenumber, by proxy of pg-libphonenumber.

CREATE EXTENSION pg_libphonenumber;


This currently installs the phone_number type which has comparison operators and functions. It stores the number in an international canonical form. This is the best compromise in my opinion.

parse_phone_number('textnumber', 'CountryCode');


Because we can tell when phone numbers equal each other and we provide an internal normal form, we can do this..

SELECT parse_phone_number('03 7010 1234', 'AU') = parse_phone_number('(03) 7010 1234', 'AU');


(returns true). This also means that DISTINCT works so we can do this to get the effect you seem to want above.

CREATE TABLE foo
AS
  SELECT DISTINCT parse_phone_number(ph, 'AU')
  FROM ( VALUES
    ('0370101234'),
    ('03 7010 1234'),
    ('(03) 7010 1234')
  ) AS t(ph);
SELECT 1


That puts in..

 parse_phone_number 
--------------------
 +61 3 7010 1234
(1 row)