CREATE EXTENSION fuzzystrmatch;
SELECT soundex('hello world!');
 soundex 
---------
 H464
(1 row)

SELECT soundex('Anne'), soundex('Ann'), difference('Anne', 'Ann');
 soundex | soundex | difference 
---------+---------+------------
 A500    | A500    |          4
(1 row)

SELECT soundex('Anne'), soundex('Andrew'), difference('Anne', 'Andrew');
 soundex | soundex | difference 
---------+---------+------------
 A500    | A536    |          2
(1 row)

SELECT soundex('Anne'), soundex('Margaret'), difference('Anne', 'Margaret');
 soundex | soundex | difference 
---------+---------+------------
 A500    | M626    |          0
(1 row)

SELECT soundex(''), difference('', '');
 soundex | difference 
---------+------------
         |          4
(1 row)

SELECT levenshtein('GUMBO', 'GAMBOL');
 levenshtein 
-------------
           2
(1 row)

SELECT levenshtein('GUMBO', 'GAMBOL', 2, 1, 1);
 levenshtein 
-------------
           3
(1 row)

SELECT levenshtein_less_equal('extensive', 'exhaustive', 2);
 levenshtein_less_equal 
------------------------
                      3
(1 row)

SELECT levenshtein_less_equal('extensive', 'exhaustive', 4);
 levenshtein_less_equal 
------------------------
                      4
(1 row)

SELECT metaphone('GUMBO', 4);
 metaphone 
-----------
 KM
(1 row)

SELECT dmetaphone('gumbo');
 dmetaphone 
------------
 KMP
(1 row)

SELECT dmetaphone_alt('gumbo');
 dmetaphone_alt 
----------------
 KMP
(1 row)