我正在开发一个用户当前播放歌曲标题的应用程序，我们在mysql数据库中查看还有谁正在播放类似的歌曲。因为同一首歌可能会在每个人的手机上有很多不同的标题，我们需要一种有效地找到尽可能接近结果的方法。
我们现在正在使用的过程从表中获取所有歌曲，然后执行foreach并将结果集中的每个条目与用户的歌曲进行比较。 以下是我们使用的函数的一部分：
$all_results = $db->select($sql);//all db entries from the songs table
foreach ( $all_results as $u ) {
$toTest = strtolower( $u['last_song'] );
$toTest = preg_replace('/[^A-Za-z0-9]/', ' ', $toTest);
$score = 0;
$score = $this->calSim( $user_last_song, $toTest, 0 ); //user last song is the current song being played by the user
if ( $score > 1 ) { //if at least there is some match then compare by another method
$score = $this->calMetaphone($user_last_song, $toTest, $score);
}
if ( $score > 5 ) {
//song matches.Push into a final array
}
}
=======================================
这是2个自定义函数：
public function calMetaphone ( $x, $y, $pts ) {
$x = metaphone( $x );
$y = metaphone( $y );
$pts = $this->calSim( $x, $y, $pts );
return $pts;
}
public function calSim ( $x, $y, $pts ) {
similar_text($x, $y, $sim);
//echo "Similarity is :$sim<br>";
if ( $sim >= 90 ) {
$pts = $pts + 5;
} else if ( $sim >= 80 ) {
$pts = $pts + 4;
}
if ( $sim >= 70 ) {
$pts = $pts + 3;
}
if ( $sim >= 60 ) {
$pts = $pts + 2;
} else {
$pts = $pts + 0;
}
return $pts;
}
但我知道这是一个非常糟糕的做法。如果数据库中有大量条目，可能需要永远地将它们全部1比1进行比较。
任何人都可以告诉我应该遵循的正确方法。
由于 卡拉姆
答案 0 :(得分：1)
我不能相信这一点但是当我需要一个类似的功能时，我发现了这个（不记得在哪里）的metaphone： -
DROP FUNCTION `func_Double_Metaphone`//
CREATE DEFINER=`aaaa`@`%` FUNCTION `func_Double_Metaphone`(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);
SET first = 3;
SET length = CHAR_LENGTH(st);
SET last = first + length -1;
SET st = CONCAT(REPEAT('-', first -1), UCASE(st), REPEAT(' ', 5)); SET is_slavo_germanic = (st LIKE '%W%' OR st LIKE '%K%' OR st LIKE '%CZ%'); SET pos = first; IF SUBSTRING(st, first, 2) IN ('GN', 'KN', 'PN', 'WR', 'PS') THEN
SET pos = pos + 1;
END IF;
IF SUBSTRING(st, first, 1) = 'X' THEN
SET pri = 'S', sec = 'S', pos = pos + 1; END IF;
WHILE pos <= last DO
SET prevpos = pos;
SET ch = SUBSTRING(st, pos, 1); CASE
WHEN ch IN ('A', 'E', 'I', 'O', 'U', 'Y') THEN
IF pos = first THEN SET pri = CONCAT(pri, 'A'), sec = CONCAT(sec, 'A'), pos = pos + 1; ELSE
SET pos = pos + 1;
END IF;
WHEN ch = 'B' THEN
IF SUBSTRING(st, pos+1, 1) = 'B' THEN
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 1; END IF;
WHEN ch = 'C' THEN
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; ELSEIF pos = first AND SUBSTRING(st, first, 6) = 'CAESAR' THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; ELSEIF SUBSTRING(st, pos, 4) = 'CHIA' THEN SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; ELSEIF SUBSTRING(st, pos, 2) = 'CH' THEN
IF pos > first AND SUBSTRING(st, pos, 4) = 'CHAE' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'X'), pos = pos + 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; 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; ELSE
IF pos > first THEN
IF SUBSTRING(st, first, 2) = 'MC' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'K'), pos = pos + 2; END IF;
ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 2; END IF;
END IF;
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; ELSEIF SUBSTRING(st, pos+1, 3) = 'CIA' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; ELSEIF SUBSTRING(st, pos, 2) = 'CC' AND NOT (pos = (first +1) AND SUBSTRING(st, first, 1) = 'M') THEN
IF SUBSTRING(st, pos+2, 1) IN ('I', 'E', 'H') AND SUBSTRING(st, pos+2, 2) != 'HU' THEN
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; ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; END IF;
ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 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; ELSEIF SUBSTRING(st, pos, 2) IN ('CI', 'CE', 'CY') THEN
IF SUBSTRING(st, pos, 3) IN ('CIO', 'CIE', 'CIA') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'X'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; END IF;
ELSE
IF SUBSTRING(st, pos+1, 2) IN (' C', ' Q', ' G') THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 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; ELSE SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; END IF;
END IF;
END IF;
WHEN ch = 'D' THEN
IF SUBSTRING(st, pos, 2) = 'DG' THEN
IF SUBSTRING(st, pos+2, 1) IN ('I', 'E', 'Y') THEN SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 3; ELSE
SET pri = CONCAT(pri, 'TK'), sec = CONCAT(sec, 'TK'), pos = pos + 2; END IF;
ELSEIF SUBSTRING(st, pos, 2) IN ('DT', 'DD') THEN
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 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; ELSEIF pos = first AND SUBSTRING(st, pos+2, 1) = 'I' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 2; 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; ELSE
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; ELSEIF pos > first AND SUBSTRING(st, pos-1, 1) != 'I' THEN
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 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; ELSE
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; ELSE
SET pri = CONCAT(pri, 'KN'), sec = CONCAT(sec, 'KN'), pos = pos + 2; END IF;
END IF;
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; 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; 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; ELSEIF SUBSTRING(st, pos+1, 1) IN ('E', 'I', 'Y') OR SUBSTRING(st, pos-1, 4) IN ('AGGI', 'OGGI') THEN
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; ELSE
IF SUBSTRING(st, pos+1, 4) = 'IER ' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'K'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; END IF;
WHEN ch = 'H' THEN
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; ELSE SET pos = pos + 1; END IF;
WHEN ch = 'J' THEN
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'); ELSE
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'H'); END IF;
ELSEIF pos = first AND SUBSTRING(st, pos, 4) != 'JOSE' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'A'); ELSE
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'); ELSE
IF pos = last THEN
SET pri = CONCAT(pri, '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'); 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; ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; END IF;
WHEN ch = 'L' THEN
IF SUBSTRING(st, pos+1, 1) = 'L' THEN
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; ELSE
SET pri = CONCAT(pri, 'L'), sec = CONCAT(sec, 'L'), pos = pos + 2; END IF;
ELSE
SET pri = CONCAT(pri, 'L'), sec = CONCAT(sec, 'L'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'M'), sec = CONCAT(sec, 'M'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'N'), sec = CONCAT(sec, 'N'), pos = pos + 1; END IF;
WHEN ch = 'P' THEN
IF SUBSTRING(st, pos+1, 1) = 'H' THEN
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 2; ELSEIF SUBSTRING(st, pos+1, 1) IN ('P', 'B') THEN SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'P'), sec = CONCAT(sec, 'P'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'K'), sec = CONCAT(sec, 'K'), pos = pos + 1; END IF;
WHEN ch = 'R' THEN
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'); ELSE
SET pri = CONCAT(pri, 'R'), sec = CONCAT(sec, '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
IF SUBSTRING(st, pos-1, 3) IN ('ISL', 'YSL') THEN
SET pos = pos + 1;
ELSEIF pos = first AND SUBSTRING(st, first, 5) = 'SUGAR' THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'S'), pos = pos + 1; ELSEIF SUBSTRING(st, pos, 2) = 'SH' THEN
IF SUBSTRING(st, pos+1, 4) IN ('HEIM', 'HOEK', 'HOLM', 'HOLZ') THEN
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 2; ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 2; END IF;
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; ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, 'S'), pos = pos + 3; END IF;
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'); 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
IF SUBSTRING(st, pos+2, 1) = 'H' THEN
IF SUBSTRING(st, pos+3, 2) IN ('OO', 'ER', 'EN', 'UY', 'ED', 'EM') THEN
IF SUBSTRING(st, pos+3, 2) IN ('ER', 'EN') THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'SK'), pos = pos + 3; ELSE
SET pri = CONCAT(pri, 'SK'), sec = CONCAT(sec, 'SK'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'SK'), sec = CONCAT(sec, 'SK'), pos = pos + 3; END IF;
ELSEIF pos = last AND SUBSTRING(st, pos-2, 2) IN ('AI', 'OI') THEN
SET sec = CONCAT(sec, 'S'), pos = pos + 1; ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, '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; ELSEIF SUBSTRING(st, pos, 3) IN ('TIA', 'TCH') THEN
SET pri = CONCAT(pri, 'X'), sec = CONCAT(sec, 'X'), pos = pos + 3; ELSEIF SUBSTRING(st, pos, 2) = 'TH' OR SUBSTRING(st, pos, 3) = 'TTH' THEN
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; ELSE
SET pri = CONCAT(pri, '0'), sec = CONCAT(sec, 'T'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'T'), sec = CONCAT(sec, 'T'), pos = pos + 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; ELSE
SET pri = CONCAT(pri, 'F'), sec = CONCAT(sec, 'F'), pos = pos + 1; END IF;
WHEN ch = 'W' THEN
IF SUBSTRING(st, pos, 2) = 'WR' THEN
SET pri = CONCAT(pri, 'R'), sec = CONCAT(sec, 'R'), pos = pos + 2; ELSEIF pos = first AND (SUBSTRING(st, pos+1, 1) IN ('A', 'E', 'I', 'O', 'U', 'Y')
OR SUBSTRING(st, pos, 2) = 'WH') THEN
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; ELSE
SET pri = CONCAT(pri, 'A'), sec = CONCAT(sec, 'A'), pos = pos + 1; END IF;
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; ELSEIF SUBSTRING(st, pos, 4) IN ('WICZ', 'WITZ') THEN
SET pri = CONCAT(pri, 'TS'), sec = CONCAT(sec, 'FX'), pos = pos + 4; ELSE SET pos = pos + 1;
END IF;
WHEN ch = 'X' THEN
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'); 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
IF SUBSTRING(st, pos+1, 1) = 'H' THEN
SET pri = CONCAT(pri, 'J'), sec = CONCAT(sec, 'J'), pos = pos + 1; 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'); ELSE
SET pri = CONCAT(pri, 'S'), sec = CONCAT(sec, '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; END CASE;
IF pos = prevpos THEN
SET pos = pos +1;
SET pri = CONCAT(pri,'<didnt incr>'); END IF;
END WHILE;
IF pri != sec THEN
SET pri = CONCAT(pri, ';', sec);
END IF;
RETURN (pri);
END
我还需要一个levenshtein函数并设法解决其中一个问题，但是性能是这样的（当比较来自多行的值时），读取行并使用levenshtein函数中构建的php要快得多。