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nnnnathann/metaphone.sql

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Created August 30, 2013 18:35
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metaphone.sql
-- This SQL implements the Double Metaphone algorythm (c) 1998, 1999 by Lawrence Philips
-- it was translated to Python, and then to SQL from the C source written by Kevin Atkinson (http://aspell.net/metaphone/)
-- By Andrew Collins - Feb, 2007 who claims no rights to this work
-- http://www.atomodo.com/code/double-metaphone/metaphone.sql/view
-- Tested with MySQL 5.1 on Ubuntu 6.01 and Ubuntu 10.4
-- Updated Nov 27, 2007 to fix a bug in the 'CC' section
-- Updated Jun 01, 2010 to fix a bug in the 'Z' section - thanks Nils Johnsson!
-- Updated Jun 25, 2010 to fix 16 signifigant bugs - thanks again Nils Johnsson for a spectacular
-- bug squashing effort. There were many cases where this function wouldn't give the same output
-- as the original C source that were fixed by his careful attention and excellent communication.
DELIMITER $$
DROP FUNCTION IF EXISTS `dm` $$
CREATE FUNCTION `dm`(st VARCHAR(55)) RETURNS varchar(128) CHARSET utf8
NO SQL
BEGIN
DECLARE length, first, last, pos, prevpos, is_slavo_germanic SMALLINT;
DECLARE pri, sec VARCHAR(45) DEFAULT '';
DECLARE ch CHAR(1);
-- returns the double metaphone code OR codes for given string
-- if there is a secondary dm it is separated with a semicolon
-- there are no checks done on the input string, but it should be a single word OR name.
-- st is short for string. I usually prefer descriptive over short, but this var is used a lot!
SET first = 3;
SET length = CHAR_LENGTH(st);
SET last = first + length -1;
SET st = CONCAT(REPEAT('-', first -1), UCASE(st), REPEAT(' ', 5)); -- pad st so we can index beyond the begining AND end of the input string
SET is_slavo_germanic = (st LIKE '%W%' OR st LIKE '%K%' OR st LIKE '%CZ%'); -- the check for '%W%' will catch WITZ
SET pos = first; -- pos is short for position
-- skip these silent letters when at start of word
IF SUBSTRING(st, first, 2) IN ('GN', 'KN', 'PN', 'WR', 'PS') THEN
SET pos = pos + 1;
END IF;
-- Initial 'X' is pronounced 'Z' e.g. 'Xavier'
IF SUBSTRING(st, first, 1) = 'X' THEN
SET pri = 'S', sec = 'S', pos = pos + 1; -- 'Z' maps to 'S'
END IF;
-- main loop through chars IN st
WHILE pos <= last DO
-- print str(pos) + '\t' + SUBSTRING(st, pos)
SET prevpos = pos;
SET ch = SUBSTRING(st, pos, 1); -- ch is short for character
CASE
WHEN ch IN ('A', 'E', 'I', 'O', 'U', 'Y') THEN
IF pos = first THEN -- all init vowels now map to 'A'
SET pri = CONCAT(pri, 'A'), sec = CONCAT(sec, 'A'), pos = pos + 1; -- nxt = ('A', 1)
ELSE
SET pos = pos + 1;
END IF;
WHEN ch = 'B' THEN
-- '-mb', e.g', 'dumb', already skipped over... see 'M' below
IF SUBSTRING(st, pos+1, 1) = 'B' THEN
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 2; -- nxt = ('P', 2)
ELSE
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 1; -- nxt = ('P', 1)
END IF;
WHEN ch = 'C' THEN
-- various germanic
IF (pos > (first + 1) AND SUBSTRING(st, pos-2, 1) NOT IN ('A', 'E', 'I', 'O', 'U', 'Y') AND SUBSTRING(st, pos-1, 3) = 'ACH' AND
(SUBSTRING(st, pos+2, 1) NOT IN ('I', 'E') OR SUBSTRING(st, pos-2, 6) IN ('BACHER', 'MACHER'))) THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
-- special case 'CAESAR'
ELSEIF pos = first AND SUBSTRING(st, first, 6) = 'CAESAR' THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; -- nxt = ('S', 2)
ELSEIF SUBSTRING(st, pos, 4) = 'CHIA' THEN -- italian 'chianti'
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSEIF SUBSTRING(st, pos, 2) = 'CH' THEN
-- find 'michael'
IF pos > first AND SUBSTRING(st, pos, 4) = 'CHAE' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'X'), pos = pos + 2; -- nxt = ('K', 'X', 2)
ELSEIF pos = first AND (SUBSTRING(st, pos+1, 5) IN ('HARAC', 'HARIS') OR
SUBSTRING(st, pos+1, 3) IN ('HOR', 'HYM', 'HIA', 'HEM')) AND SUBSTRING(st, first, 5) != 'CHORE' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
-- germanic, greek, OR otherwise 'ch' for 'kh' sound
ELSEIF SUBSTRING(st, first, 4) IN ('VAN ', 'VON ') OR SUBSTRING(st, first, 3) = 'SCH'
OR SUBSTRING(st, pos-2, 6) IN ('ORCHES', 'ARCHIT', 'ORCHID')
OR SUBSTRING(st, pos+2, 1) IN ('T', 'S')
OR ((SUBSTRING(st, pos-1, 1) IN ('A', 'O', 'U', 'E') OR pos = first)
AND SUBSTRING(st, pos+2, 1) IN ('L', 'R', 'N', 'M', 'B', 'H', 'F', 'V', 'W', ' ')) THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
IF pos > first THEN
IF SUBSTRING(st, first, 2) = 'MC' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('X', 'K', 2)
END IF;
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 2; -- nxt = ('X', 2)
END IF;
END IF;
-- e.g, 'czerny'
ELSEIF SUBSTRING(st, pos, 2) = 'CZ' AND SUBSTRING(st, pos-2, 4) != 'WICZ' THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'X'), pos = pos + 2; -- nxt = ('S', 'X', 2)
-- e.g., 'focaccia'
ELSEIF SUBSTRING(st, pos+1, 3) = 'CIA' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('X', 3)
-- double 'C', but not IF e.g. 'McClellan'
ELSEIF SUBSTRING(st, pos, 2) = 'CC' AND NOT (pos = (first +1) AND SUBSTRING(st, first, 1) = 'M') THEN
-- 'bellocchio' but not 'bacchus'
IF SUBSTRING(st, pos+2, 1) IN ('I', 'E', 'H') AND SUBSTRING(st, pos+2, 2) != 'HU' THEN
-- 'accident', 'accede' 'succeed'
IF (pos = first +1 AND SUBSTRING(st, first) = 'A') OR
SUBSTRING(st, pos-1, 5) IN ('UCCEE', 'UCCES') THEN
SET pri = CONCAT(pri, 'KS'), sec = CONCAT(sec, 'KS'), pos = pos + 3; -- nxt = ('KS', 3)
-- 'bacci', 'bertucci', other italian
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('X', 3)
END IF;
ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
END IF;
ELSEIF SUBSTRING(st, pos, 2) IN ('CK', 'CG', 'CQ') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 'K', 2)
ELSEIF SUBSTRING(st, pos, 2) IN ('CI', 'CE', 'CY') THEN
-- italian vs. english
IF SUBSTRING(st, pos, 3) IN ('CIO', 'CIE', 'CIA') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'X'), pos = pos + 2; -- nxt = ('S', 'X', 2)
ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; -- nxt = ('S', 2)
END IF;
ELSE
-- name sent IN 'mac caffrey', 'mac gregor
IF SUBSTRING(st, pos+1, 2) IN (' C', ' Q', ' G') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 3; -- nxt = ('K', 3)
ELSE
IF SUBSTRING(st, pos+1, 1) IN ('C', 'K', 'Q') AND SUBSTRING(st, pos+1, 2) NOT IN ('CE', 'CI') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE -- default for 'C'
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; -- nxt = ('K', 1)
END IF;
END IF;
END IF;
-- ELSEIF ch = 'Ç' THEN -- will never get here with st.encode('ascii', 'replace') above
-- SET pri = CONCAT(pri, '5'), sec = CONCAT(sec, '5'), pos = pos + 1; -- nxt = ('S', 1)
WHEN ch = 'D' THEN
IF SUBSTRING(st, pos, 2) = 'DG' THEN
IF SUBSTRING(st, pos+2, 1) IN ('I', 'E', 'Y') THEN -- e.g. 'edge'
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 3; -- nxt = ('J', 3)
ELSE
SET pri = CONCAT(pri, 'TK'), sec = CONCAT(sec, 'TK'), pos = pos + 2; -- nxt = ('TK', 2)
END IF;
ELSEIF SUBSTRING(st, pos, 2) IN ('DT', 'DD') THEN
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 2; -- nxt = ('T', 2)
ELSE
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 1; -- nxt = ('T', 1)
END IF;
WHEN ch = 'F' THEN
IF SUBSTRING(st, pos+1, 1) = 'F' THEN
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 2; -- nxt = ('F', 2)
ELSE
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 1; -- nxt = ('F', 1)
END IF;
WHEN ch = 'G' THEN
IF SUBSTRING(st, pos+1, 1) = 'H' THEN
IF (pos > first AND SUBSTRING(st, pos-1, 1) NOT IN ('A', 'E', 'I', 'O', 'U', 'Y'))
OR ( pos = first AND SUBSTRING(st, pos+2, 1) != 'I') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSEIF pos = first AND SUBSTRING(st, pos+2, 1) = 'I' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 2; -- nxt = ('J', 2)
-- Parker's rule (with some further refinements) - e.g., 'hugh'
ELSEIF (pos > (first + 1) AND SUBSTRING(st, pos-2, 1) IN ('B', 'H', 'D') )
OR (pos > (first + 2) AND SUBSTRING(st, pos-3, 1) IN ('B', 'H', 'D') )
OR (pos > (first + 3) AND SUBSTRING(st, pos-4, 1) IN ('B', 'H') ) THEN
SET pos = pos + 2; -- nxt = (None, 2)
ELSE
-- e.g., 'laugh', 'McLaughlin', 'cough', 'gough', 'rough', 'tough'
IF pos > (first + 2) AND SUBSTRING(st, pos-1, 1) = 'U'
AND SUBSTRING(st, pos-3, 1) IN ('C', 'G', 'L', 'R', 'T') THEN
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 2; -- nxt = ('F', 2)
ELSEIF pos > first AND SUBSTRING(st, pos-1, 1) != 'I' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
SET pos = pos + 1;
END IF;
END IF;
ELSEIF SUBSTRING(st, pos+1, 1) = 'N' THEN
IF pos = (first +1) AND SUBSTRING(st, first, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y') AND NOT is_slavo_germanic THEN
SET pri = CONCAT(pri, 'KN'), sec = CONCAT(sec, 'N'), pos = pos + 2; -- nxt = ('KN', 'N', 2)
ELSE
-- not e.g. 'cagney'
IF SUBSTRING(st, pos+2, 2) != 'EY' AND SUBSTRING(st, pos+1, 1) != 'Y'
AND NOT is_slavo_germanic THEN
SET pri = CONCAT(pri, 'N'), sec = CONCAT(sec, 'KN'), pos = pos + 2; -- nxt = ('N', 'KN', 2)
ELSE
SET pri = CONCAT(pri, 'KN'), sec = CONCAT(sec, 'KN'), pos = pos + 2; -- nxt = ('KN', 2)
END IF;
END IF;
-- 'tagliaro'
ELSEIF SUBSTRING(st, pos+1, 2) = 'LI' AND NOT is_slavo_germanic THEN
SET pri = CONCAT(pri, 'KL'), sec = CONCAT(sec, 'L'), pos = pos + 2; -- nxt = ('KL', 'L', 2)
-- -ges-,-gep-,-gel-, -gie- at beginning
ELSEIF pos = first AND (SUBSTRING(st, pos+1, 1) = 'Y'
OR SUBSTRING(st, pos+1, 2) IN ('ES', 'EP', 'EB', 'EL', 'EY', 'IB', 'IL', 'IN', 'IE', 'EI', 'ER')) THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'J'), pos = pos + 2; -- nxt = ('K', 'J', 2)
-- -ger-, -gy-
ELSEIF (SUBSTRING(st, pos+1, 2) = 'ER' OR SUBSTRING(st, pos+1, 1) = 'Y')
AND SUBSTRING(st, first, 6) NOT IN ('DANGER', 'RANGER', 'MANGER')
AND SUBSTRING(st, pos-1, 1) not IN ('E', 'I') AND SUBSTRING(st, pos-1, 3) NOT IN ('RGY', 'OGY') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'J'), pos = pos + 2; -- nxt = ('K', 'J', 2)
-- italian e.g, 'biaggi'
ELSEIF SUBSTRING(st, pos+1, 1) IN ('E', 'I', 'Y') OR SUBSTRING(st, pos-1, 4) IN ('AGGI', 'OGGI') THEN
-- obvious germanic
IF SUBSTRING(st, first, 4) IN ('VON ', 'VAN ') OR SUBSTRING(st, first, 3) = 'SCH'
OR SUBSTRING(st, pos+1, 2) = 'ET' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
-- always soft IF french ending
IF SUBSTRING(st, pos+1, 4) = 'IER ' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 2; -- nxt = ('J', 2)
ELSE
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('J', 'K', 2)
END IF;
END IF;
ELSEIF SUBSTRING(st, pos+1, 1) = 'G' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; -- nxt = ('K', 1)
END IF;
WHEN ch = 'H' THEN
-- only keep IF first & before vowel OR btw. 2 ('A', 'E', 'I', 'O', 'U', 'Y')
IF (pos = first OR SUBSTRING(st, pos-1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y'))
AND SUBSTRING(st, pos+1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y') THEN
SET pri = CONCAT(pri, 'H'), sec = CONCAT(sec, 'H'), pos = pos + 2; -- nxt = ('H', 2)
ELSE -- (also takes care of 'HH')
SET pos = pos + 1; -- nxt = (None, 1)
END IF;
WHEN ch = 'J' THEN
-- obvious spanish, 'jose', 'san jacinto'
IF SUBSTRING(st, pos, 4) = 'JOSE' OR SUBSTRING(st, first, 4) = 'SAN ' THEN
IF (pos = first AND SUBSTRING(st, pos+4, 1) = ' ') OR SUBSTRING(st, first, 4) = 'SAN ' THEN
SET pri = CONCAT(pri, 'H'), sec = CONCAT(sec, 'H'); -- nxt = ('H',)
ELSE
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'H'); -- nxt = ('J', 'H')
END IF;
ELSEIF pos = first AND SUBSTRING(st, pos, 4) != 'JOSE' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'A'); -- nxt = ('J', 'A') -- Yankelovich/Jankelowicz
ELSE
-- spanish pron. of e.g. 'bajador'
IF SUBSTRING(st, pos-1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y') AND NOT is_slavo_germanic
AND SUBSTRING(st, pos+1, 1) IN ('A', 'O') THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'H'); -- nxt = ('J', 'H')
ELSE
IF pos = last THEN
SET pri = CONCAT(pri, 'J'); -- nxt = ('J', ' ')
ELSE
IF SUBSTRING(st, pos+1, 1) not IN ('L', 'T', 'K', 'S', 'N', 'M', 'B', 'Z')
AND SUBSTRING(st, pos-1, 1) not IN ('S', 'K', 'L') THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'); -- nxt = ('J',)
END IF;
END IF;
END IF;
END IF;
IF SUBSTRING(st, pos+1, 1) = 'J' THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
WHEN ch = 'K' THEN
IF SUBSTRING(st, pos+1, 1) = 'K' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; -- nxt = ('K', 1)
END IF;
WHEN ch = 'L' THEN
IF SUBSTRING(st, pos+1, 1) = 'L' THEN
-- spanish e.g. 'cabrillo', 'gallegos'
IF (pos = (last - 2) AND SUBSTRING(st, pos-1, 4) IN ('ILLO', 'ILLA', 'ALLE'))
OR ((SUBSTRING(st, last-1, 2) IN ('AS', 'OS') OR SUBSTRING(st, last) IN ('A', 'O'))
AND SUBSTRING(st, pos-1, 4) = 'ALLE') THEN
SET pri = CONCAT(pri, 'L'), pos = pos + 2; -- nxt = ('L', ' ', 2)
ELSE
SET pri = CONCAT(pri, 'L'), sec = CONCAT(sec, 'L'), pos = pos + 2; -- nxt = ('L', 2)
END IF;
ELSE
SET pri = CONCAT(pri, 'L'), sec = CONCAT(sec, 'L'), pos = pos + 1; -- nxt = ('L', 1)
END IF;
WHEN ch = 'M' THEN
IF SUBSTRING(st, pos-1, 3) = 'UMB'
AND (pos + 1 = last OR SUBSTRING(st, pos+2, 2) = 'ER')
OR SUBSTRING(st, pos+1, 1) = 'M' THEN
SET pri = CONCAT(pri, 'M'), sec = CONCAT(sec, 'M'), pos = pos + 2; -- nxt = ('M', 2)
ELSE
SET pri = CONCAT(pri, 'M'), sec = CONCAT(sec, 'M'), pos = pos + 1; -- nxt = ('M', 1)
END IF;
WHEN ch = 'N' THEN
IF SUBSTRING(st, pos+1, 1) = 'N' THEN
SET pri = CONCAT(pri, 'N'), sec = CONCAT(sec, 'N'), pos = pos + 2; -- nxt = ('N', 2)
ELSE
SET pri = CONCAT(pri, 'N'), sec = CONCAT(sec, 'N'), pos = pos + 1; -- nxt = ('N', 1)
END IF;
-- ELSEIF ch = u'Ñ' THEN
-- SET pri = CONCAT(pri, '5'), sec = CONCAT(sec, '5'), pos = pos + 1; -- nxt = ('N', 1)
WHEN ch = 'P' THEN
IF SUBSTRING(st, pos+1, 1) = 'H' THEN
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 2; -- nxt = ('F', 2)
ELSEIF SUBSTRING(st, pos+1, 1) IN ('P', 'B') THEN -- also account for 'campbell', 'raspberry'
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 2; -- nxt = ('P', 2)
ELSE
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 1; -- nxt = ('P', 1)
END IF;
WHEN ch = 'Q' THEN
IF SUBSTRING(st, pos+1, 1) = 'Q' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; -- nxt = ('K', 2)
ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; -- nxt = ('K', 1)
END IF;
WHEN ch = 'R' THEN
-- french e.g. 'rogier', but exclude 'hochmeier'
IF pos = last AND not is_slavo_germanic
AND SUBSTRING(st, pos-2, 2) = 'IE' AND SUBSTRING(st, pos-4, 2) NOT IN ('ME', 'MA') THEN
SET sec = CONCAT(sec, 'R'); -- nxt = ('', 'R')
ELSE
SET pri = CONCAT(pri, 'R'), sec = CONCAT(sec, 'R'); -- nxt = ('R',)
END IF;
IF SUBSTRING(st, pos+1, 1) = 'R' THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
WHEN ch = 'S' THEN
-- special cases 'island', 'isle', 'carlisle', 'carlysle'
IF SUBSTRING(st, pos-1, 3) IN ('ISL', 'YSL') THEN
SET pos = pos + 1;
-- special case 'sugar-'
ELSEIF pos = first AND SUBSTRING(st, first, 5) = 'SUGAR' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'S'), pos = pos + 1; -- nxt =('X', 'S', 1)
ELSEIF SUBSTRING(st, pos, 2) = 'SH' THEN
-- germanic
IF SUBSTRING(st, pos+1, 4) IN ('HEIM', 'HOEK', 'HOLM', 'HOLZ') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; -- nxt = ('S', 2)
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 2; -- nxt = ('X', 2)
END IF;
-- italian & armenian
ELSEIF SUBSTRING(st, pos, 3) IN ('SIO', 'SIA') OR SUBSTRING(st, pos, 4) = 'SIAN' THEN
IF NOT is_slavo_germanic THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('S', 'X', 3)
ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 3; -- nxt = ('S', 3)
END IF;
-- german & anglicisations, e.g. 'smith' match 'schmidt', 'snider' match 'schneider'
-- also, -sz- IN slavic language altho IN hungarian it is pronounced 's'
ELSEIF (pos = first AND SUBSTRING(st, pos+1, 1) IN ('M', 'N', 'L', 'W')) OR SUBSTRING(st, pos+1, 1) = 'Z' THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'X'); -- nxt = ('S', 'X')
IF SUBSTRING(st, pos+1, 1) = 'Z' THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
ELSEIF SUBSTRING(st, pos, 2) = 'SC' THEN
-- Schlesinger's rule
IF SUBSTRING(st, pos+2, 1) = 'H' THEN
-- dutch origin, e.g. 'school', 'schooner'
IF SUBSTRING(st, pos+3, 2) IN ('OO', 'ER', 'EN', 'UY', 'ED', 'EM') THEN
-- 'schermerhorn', 'schenker'
IF SUBSTRING(st, pos+3, 2) IN ('ER', 'EN') THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'SK'), pos = pos + 3; -- nxt = ('X', 'SK', 3)
ELSE
SET pri = CONCAT(pri, 'SK'), sec = CONCAT(sec, 'SK'), pos = pos + 3; -- nxt = ('SK', 3)
END IF;
ELSE
IF pos = first AND SUBSTRING(st, first+3, 1) not IN ('A', 'E', 'I', 'O', 'U', 'Y') AND SUBSTRING(st, first+3, 1) != 'W' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'S'), pos = pos + 3; -- nxt = ('X', 'S', 3)
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('X', 3)
END IF;
END IF;
ELSEIF SUBSTRING(st, pos+2, 1) IN ('I', 'E', 'Y') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 3; -- nxt = ('S', 3)
ELSE
SET pri = CONCAT(pri, 'SK'), sec = CONCAT(sec, 'SK'), pos = pos + 3; -- nxt = ('SK', 3)
END IF;
-- french e.g. 'resnais', 'artois'
ELSEIF pos = last AND SUBSTRING(st, pos-2, 2) IN ('AI', 'OI') THEN
SET sec = CONCAT(sec, 'S'), pos = pos + 1; -- nxt = ('', 'S')
ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'); -- nxt = ('S',)
IF SUBSTRING(st, pos+1, 1) IN ('S', 'Z') THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
END IF;
WHEN ch = 'T' THEN
IF SUBSTRING(st, pos, 4) = 'TION' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('X', 3)
ELSEIF SUBSTRING(st, pos, 3) IN ('TIA', 'TCH') THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; -- nxt = ('X', 3)
ELSEIF SUBSTRING(st, pos, 2) = 'TH' OR SUBSTRING(st, pos, 3) = 'TTH' THEN
-- special case 'thomas', 'thames' OR germanic
IF SUBSTRING(st, pos+2, 2) IN ('OM', 'AM') OR SUBSTRING(st, first, 4) IN ('VON ', 'VAN ')
OR SUBSTRING(st, first, 3) = 'SCH' THEN
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 2; -- nxt = ('T', 2)
ELSE
SET pri = CONCAT(pri, '0'), sec = CONCAT(sec, 'T'), pos = pos + 2; -- nxt = ('0', 'T', 2)
END IF;
ELSEIF SUBSTRING(st, pos+1, 1) IN ('T', 'D') THEN
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 2; -- nxt = ('T', 2)
ELSE
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 1; -- nxt = ('T', 1)
END IF;
WHEN ch = 'V' THEN
IF SUBSTRING(st, pos+1, 1) = 'V' THEN
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 2; -- nxt = ('F', 2)
ELSE
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 1; -- nxt = ('F', 1)
END IF;
WHEN ch = 'W' THEN
-- can also be IN middle of word
IF SUBSTRING(st, pos, 2) = 'WR' THEN
SET pri = CONCAT(pri, 'R'), sec = CONCAT(sec, 'R'), pos = pos + 2; -- nxt = ('R', 2)
ELSEIF pos = first AND (SUBSTRING(st, pos+1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y')
OR SUBSTRING(st, pos, 2) = 'WH') THEN
-- Wasserman should match Vasserman
IF SUBSTRING(st, pos+1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y') THEN
SET pri = CONCAT(pri, 'A'), sec = CONCAT(sec, 'F'), pos = pos + 1; -- nxt = ('A', 'F', 1)
ELSE
SET pri = CONCAT(pri, 'A'), sec = CONCAT(sec, 'A'), pos = pos + 1; -- nxt = ('A', 1)
END IF;
-- Arnow should match Arnoff
ELSEIF (pos = last AND SUBSTRING(st, pos-1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y'))
OR SUBSTRING(st, pos-1, 5) IN ('EWSKI', 'EWSKY', 'OWSKI', 'OWSKY')
OR SUBSTRING(st, first, 3) = 'SCH' THEN
SET sec = CONCAT(sec, 'F'), pos = pos + 1; -- nxt = ('', 'F', 1)
-- END IF;
-- polish e.g. 'filipowicz'
ELSEIF SUBSTRING(st, pos, 4) IN ('WICZ', 'WITZ') THEN
SET pri = CONCAT(pri, 'TS'), sec = CONCAT(sec, 'FX'), pos = pos + 4; -- nxt = ('TS', 'FX', 4)
ELSE -- default is to skip it
SET pos = pos + 1;
END IF;
WHEN ch = 'X' THEN
-- french e.g. breaux
IF not(pos = last AND (SUBSTRING(st, pos-3, 3) IN ('IAU', 'EAU')
OR SUBSTRING(st, pos-2, 2) IN ('AU', 'OU'))) THEN
SET pri = CONCAT(pri, 'KS'), sec = CONCAT(sec, 'KS'); -- nxt = ('KS',)
END IF;
IF SUBSTRING(st, pos+1, 1) IN ('C', 'X') THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
WHEN ch = 'Z' THEN
-- chinese pinyin e.g. 'zhao'
IF SUBSTRING(st, pos+1, 1) = 'H' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 1; -- nxt = ('J', 2)
ELSEIF SUBSTRING(st, pos+1, 3) IN ('ZO', 'ZI', 'ZA')
OR (is_slavo_germanic AND pos > first AND SUBSTRING(st, pos-1, 1) != 'T') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'TS'); -- nxt = ('S', 'TS')
ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'); -- nxt = ('S',)
END IF;
IF SUBSTRING(st, pos+1, 1) = 'Z' THEN
SET pos = pos + 2;
ELSE
SET pos = pos + 1;
END IF;
ELSE
SET pos = pos + 1; -- DEFAULT is to move to next char
END CASE;
IF pos = prevpos THEN
SET pos = pos +1;
SET pri = CONCAT(pri,'<didnt incr>'); -- it might be better to throw an error here if you really must be accurate
END IF;
END WHILE;
IF pri != sec THEN
SET pri = CONCAT(pri, ';', sec);
END IF;
RETURN (pri);
END $$
DELIMITER ;
select code from sites_codes where dm( column ) = dm( 'search string' );
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