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)

-- Wovels
SELECT daitch_mokotoff('Augsburg');
 daitch_mokotoff 
-----------------
 {054795}
(1 row)

SELECT daitch_mokotoff('Breuer');
 daitch_mokotoff 
-----------------
 {791900}
(1 row)

SELECT daitch_mokotoff('Freud');
 daitch_mokotoff 
-----------------
 {793000}
(1 row)

-- The letter "H"
SELECT daitch_mokotoff('Halberstadt');
 daitch_mokotoff 
-----------------
 {587943,587433}
(1 row)

SELECT daitch_mokotoff('Mannheim');
 daitch_mokotoff 
-----------------
 {665600}
(1 row)

-- Adjacent sounds
SELECT daitch_mokotoff('Chernowitz');
 daitch_mokotoff 
-----------------
 {596740,496740}
(1 row)

-- Adjacent letters with identical adjacent code digits
SELECT daitch_mokotoff('Cherkassy');
 daitch_mokotoff 
-----------------
 {595400,495400}
(1 row)

SELECT daitch_mokotoff('Kleinman');
 daitch_mokotoff 
-----------------
 {586660}
(1 row)

-- More than one word
SELECT daitch_mokotoff('Nowy Targ');
 daitch_mokotoff 
-----------------
 {673950}
(1 row)

-- Padded with "0"
SELECT daitch_mokotoff('Berlin');
 daitch_mokotoff 
-----------------
 {798600}
(1 row)

-- Other examples from https://www.avotaynu.com/soundex.htm
SELECT daitch_mokotoff('Ceniow');
 daitch_mokotoff 
-----------------
 {567000,467000}
(1 row)

SELECT daitch_mokotoff('Tsenyuv');
 daitch_mokotoff 
-----------------
 {467000}
(1 row)

SELECT daitch_mokotoff('Holubica');
 daitch_mokotoff 
-----------------
 {587500,587400}
(1 row)

SELECT daitch_mokotoff('Golubitsa');
 daitch_mokotoff 
-----------------
 {587400}
(1 row)

SELECT daitch_mokotoff('Przemysl');
 daitch_mokotoff 
-----------------
 {794648,746480}
(1 row)

SELECT daitch_mokotoff('Pshemeshil');
 daitch_mokotoff 
-----------------
 {746480}
(1 row)

SELECT daitch_mokotoff('Rosochowaciec');
                      daitch_mokotoff                      
-----------------------------------------------------------
 {945755,945754,945745,945744,944755,944754,944745,944744}
(1 row)

SELECT daitch_mokotoff('Rosokhovatsets');
 daitch_mokotoff 
-----------------
 {945744}
(1 row)

-- Ignored characters
SELECT daitch_mokotoff('''OBrien');
 daitch_mokotoff 
-----------------
 {079600}
(1 row)

SELECT daitch_mokotoff('O''Brien');
 daitch_mokotoff 
-----------------
 {079600}
(1 row)

-- "Difficult" cases, likely to cause trouble for other implementations.
SELECT daitch_mokotoff('CJC');
               daitch_mokotoff               
---------------------------------------------
 {550000,540000,545000,450000,400000,440000}
(1 row)

SELECT daitch_mokotoff('BESST');
 daitch_mokotoff 
-----------------
 {743000}
(1 row)

SELECT daitch_mokotoff('BOUEY');
 daitch_mokotoff 
-----------------
 {710000}
(1 row)

SELECT daitch_mokotoff('HANNMANN');
 daitch_mokotoff 
-----------------
 {566600}
(1 row)

SELECT daitch_mokotoff('MCCOYJR');
                      daitch_mokotoff                      
-----------------------------------------------------------
 {651900,654900,654190,654490,645190,645490,641900,644900}
(1 row)

SELECT daitch_mokotoff('ACCURSO');
                      daitch_mokotoff                      
-----------------------------------------------------------
 {059400,054000,054940,054400,045940,045400,049400,044000}
(1 row)

SELECT daitch_mokotoff('BIERSCHBACH');
                      daitch_mokotoff                      
-----------------------------------------------------------
 {794575,794574,794750,794740,745750,745740,747500,747400}
(1 row)