postgresql/contrib/soundex

This directory contains a module that implements the "Soundex" code as
a PostgreSQL user-defined function.  The Soundex system is a method of
matching similar sounding names (or any words) to the same code.  It
was initially used by the United States Census in 1880, 1900, and
1910, but it has little use beyond English names (or the English
pronunciation of names), and it is not a linguistic tool.

To install it, first configure the main source tree, then run make;
make install in this directory.  Finally, load the function definition
with psql:

    psql -f PREFIX/share/contrib/soundex.sql

The following are some usage examples:

SELECT text_soundex('hello world!');

CREATE TABLE s (nm text)\g

insert into s values ('john')\g
insert into s values ('joan')\g
insert into s values ('wobbly')\g

select * from s
where text_soundex(nm) = text_soundex('john')\g

select nm from s a, s b
where text_soundex(a.nm) = text_soundex(b.nm)
and a.oid <> b.oid\g

CREATE FUNCTION text_sx_eq(text, text) RETURNS bool AS
'select text_soundex($1) = text_soundex($2)'
LANGUAGE 'sql'\g

CREATE FUNCTION text_sx_lt(text,text) RETURNS bool AS
'select text_soundex($1) < text_soundex($2)'
LANGUAGE 'sql'\g

CREATE FUNCTION text_sx_gt(text,text) RETURNS bool AS
'select text_soundex($1) > text_soundex($2)'
LANGUAGE 'sql';

CREATE FUNCTION text_sx_le(text,text) RETURNS bool AS
'select text_soundex($1) <= text_soundex($2)'
LANGUAGE 'sql';

CREATE FUNCTION text_sx_ge(text,text) RETURNS bool AS
'select text_soundex($1) >= text_soundex($2)'
LANGUAGE 'sql';

CREATE FUNCTION text_sx_ne(text,text) RETURNS bool AS
'select text_soundex($1) <> text_soundex($2)'
LANGUAGE 'sql';

DROP OPERATOR #= (text,text)\g

CREATE OPERATOR #= (leftarg=text, rightarg=text, procedure=text_sx_eq,
commutator=text_sx_eq)\g

SELECT *
FROM s
WHERE text_sx_eq(nm,'john')\g

SELECT *
from s
where s.nm #= 'john';