Description:
MySQL 5.7 introduce mecab & ngram parser.
But fulltext search with mecab, don't work as manual(=builtin parser).
The manual said as belows, but match "some noise words" with mecab.
https://dev.mysql.com/doc/refman/5.7/en/fulltext-boolean.html
'"some words"'
Find rows that contain the exact phrase “some words” (for example, rows that contain “some words of wisdom” but not “some noise words”). Note that the " characters that enclose the phrase are operator characters that delimit the phrase. They are not the quotation marks that enclose the search string itself.
How to repeat:
(1) builtin parser works as manual.
drop table if exists `searches`;
CREATE TABLE `searches` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`search_description` mediumtext NOT NULL,
PRIMARY KEY (`id`),
FULLTEXT KEY `idx_desc` (`search_description`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
insert into searches values(1 ,'some words of wisdom'),(2, 'some noise words'),(3, 'some, words of wisdom'),(4, 'words, some people'),(5, 'words, erros from some people');
select id,search_description from searches where match (search_description) against ('"some words"' in boolean mode);
+----+-----------------------+
| id | search_description |
+----+-----------------------+
| 1 | some words of wisdom |
| 3 | some, words of wisdom |
+----+-----------------------+
2 rows in set (0.01 sec)
(2) mecab parser don't work as manual.
drop table if exists `searches2`;
CREATE TABLE `searches2` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`search_description` mediumtext NOT NULL,
PRIMARY KEY (`id`),
FULLTEXT KEY `idx_desc` (`search_description`) /*!50100 WITH PARSER `mecab` */
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
insert into searches2 values(1 ,'some words of wisdom'),(2, 'some noise words'),(3, 'some, words of wisdom'),(4, 'words, some people'),(5, 'words, erros from some people');
select id,search_description from searches2 where match (search_description) against ('"some words"' in boolean mode);
+----+-----------------------+
| id | search_description |
+----+-----------------------+
| 1 | some words of wisdom |
| 2 | some noise words |
| 3 | some, words of wisdom |
+----+-----------------------+
3 rows in set (0.02 sec)
Suggested fix:
Modify fulltext search with mecab to keep compatibility.
or describe the difference between builtin and mecab in the manual.
