MySQL 如何在mysql中添加levenshtein函数？
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How to add levenshtein function in mysql?
提问by Sandesh Sharma
I got the code for levenshtein distance for mysql form "http://kristiannissen.wordpress.com/2010/07/08/mysql-levenshtein/" but, how to add that function in mysql? I am using xampp and i need it for search in php.
我得到了 mysql 表单“http://kristiannissen.wordpress.com/2010/07/08/mysql-levenshtein/”的 levenshtein 距离的代码，但是，如何在 mysql 中添加该函数？我正在使用 xampp，我需要它在 php 中进行搜索。
回答by mvp
I have connected to my MySQL server and simply executed this statementin MySQL Workbench, and it simply worked - I now have new function levenshtein().
我已经连接到我的 MySQL 服务器并在MySQL Workbench 中简单地执行了这个语句，它很简单地工作 - 我现在有了新功能。levenshtein()
For example, this works as expected:
例如，这按预期工作：
SELECT levenshtein('abcde', 'abced')
2
回答by KEYAN TECH
DELIMITER $$
CREATE FUNCTION levenshtein( s1 VARCHAR(255), s2 VARCHAR(255) )
RETURNS INT
DETERMINISTIC
BEGIN
DECLARE s1_len, s2_len, i, j, c, c_temp, cost INT;
DECLARE s1_char CHAR;
-- max strlen=255
DECLARE cv0, cv1 VARBINARY(256);
SET s1_len = CHAR_LENGTH(s1), s2_len = CHAR_LENGTH(s2), cv1 = 0x00, j = 1, i = 1, c = 0;
IF s1 = s2 THEN
RETURN 0;
ELSEIF s1_len = 0 THEN
RETURN s2_len;
ELSEIF s2_len = 0 THEN
RETURN s1_len;
ELSE
WHILE j <= s2_len DO
SET cv1 = CONCAT(cv1, UNHEX(HEX(j))), j = j + 1;
END WHILE;
WHILE i <= s1_len DO
SET s1_char = SUBSTRING(s1, i, 1), c = i, cv0 = UNHEX(HEX(i)), j = 1;
WHILE j <= s2_len DO
SET c = c + 1;
IF s1_char = SUBSTRING(s2, j, 1) THEN
SET cost = 0; ELSE SET cost = 1;
END IF;
SET c_temp = CONV(HEX(SUBSTRING(cv1, j, 1)), 16, 10) + cost;
IF c > c_temp THEN SET c = c_temp; END IF;
SET c_temp = CONV(HEX(SUBSTRING(cv1, j+1, 1)), 16, 10) + 1;
IF c > c_temp THEN
SET c = c_temp;
END IF;
SET cv0 = CONCAT(cv0, UNHEX(HEX(c))), j = j + 1;
END WHILE;
SET cv1 = cv0, i = i + 1;
END WHILE;
END IF;
RETURN c;
END$$
DELIMITER ;
回答by MSS
the web paged linked in question is dead. By the way, the function's create code is here:
有问题的网页链接已死。顺便说一下，函数的创建代码在这里：
DELIMITER $$
CREATE FUNCTION levenshtein( s1 varchar(255), s2 varchar(255) ) returns int deterministic
BEGIN
DECLARE s1_len,
s2_len,
i,
j,
c,
c_temp,
cost int;
declare s1_char char;
-- max strlen=255
declare cv0,
cv1 varbinary(256);
set s1_len = char_length(s1),
s2_len = char_length(s2),
cv1 = 0x00,
j = 1,
i = 1,
c = 0;
if s1 = s2 THEN
RETURN 0;
elseif s1_len = 0 THEN
RETURN s2_len;
elseif s2_len = 0 THEN
RETURN s1_len;
else
WHILE j <= s2_len do
SET cv1 = concat(cv1, unhex(hex(j))),
j = j + 1;
endWHILE;WHILE i <= s1_len do
SET s1_char = substring(s1, i, 1),
c = i,
cv0 = unhex(hex(i)),
j = 1;WHILE j <= s2_len do
SET c = c + 1;IF s1_char = Substring(s2, j, 1) then
SET cost = 0;
else
SET cost = 1;ENDIF;SET c_temp = conv(hex(substring(cv1, j, 1)), 16, 10) + cost;IF c > c_temp then
SET c = c_temp;ENDIF;SET c_temp = conv(hex(substring(cv1, j+1, 1)), 16, 10) + 1;IF c > c_temp then
SET c = c_temp;ENDIF;SET cv0 = concat(cv0, unhex(hex(c))),
j = j + 1;ENDWHILE;SET cv1 = cv0,
i = i + 1;ENDWHILE;ENDIF;RETURN c;
END;
DELIMITER ;
I hope it helps some body!
希望对身体有帮助！
回答by Chella
- Login to mysql database through phpmyadmin or through terminal.
click sql.
add delimiter $$to your the function in the above link and at the end delimiter ;.
- once if it successfully compiled you can use it in that database wherever you want like inside of another procedures or functions or queries etc..!
- 通过phpmyadmin或终端登录mysql数据库。
单击 sql。
将分隔符 $$添加到上述链接中的函数中，并在最后分隔符；.
- 一旦成功编译，您就可以在该数据库中的任何地方使用它，例如在另一个过程或函数或查询等中……！
