问题描述

这是我测试过的.

mysql> select * from product;
+------------+---------+---------------+
| Id         | Product | ProductIdType |
+------------+---------+---------------+
| B00005N5PF | one pen | ASIN          |
| B000J5XS3C |         | ASIN          |
+------------+---------+---------------+
2 rows in set (0.00 sec)

mysql> select * from product p where match (p.Product) against ('pen' in boolean mode);
Empty set (0.00 sec)

mysql> select * from product p where match (p.Product) against ('one pen' in boolean mode);
Empty set (0.00 sec)

这是创建语句.

CREATE TABLE product
(
    Id                VARCHAR(16),
    Product           VARCHAR(128),
    ProductIdType     VARCHAR(8),
  PRIMARY KEY (Id),
  FULLTEXT (Product)
) ENGINE=MyISAM;

等号和LIKE"工作正常.那么为什么?

Equal sign and 'LIKE' work fine. So Why?

推荐答案

-- drop table testproduct;
CREATE TABLE testproduct
(
    Id                VARCHAR(16),
    prod_name           TEXT,
    ProductIdType     VARCHAR(8),
  PRIMARY KEY (Id),
  FULLTEXT (prod_name)
) ENGINE=MyISAM;

insert into testproduct (id,prod_name,productidtype) values ('B00005N5PF','one pen and a good price for a pen','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('B570J5XS3C',null,'ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C00ZZ5N5PF','let us get rid of some noise','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('D00LL5N5PA','four score and seven years ago our fore...','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('EEEZZ5N5PF','he has a harpoon','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C01ZZ5N5PF','and then we','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('B00ZZ5N5PF','he has a pen in his pocket not a banana','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C02ZZ5N5PF','went to the store','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C03ZZ5N5PF','and decided that we should buy some','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C04ZZ5N5PF','fruit cups or fruit or berries or pebbles','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C037Z5N5PF','then he and her she and it','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('C04K95N5PF','threw some daggers and a harpoon','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('D88895N5PF','more noise and some of this','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('D34595N5PF','this article about harpoons really drills into the throwing of harpoon or harpoons to those that deserve a harpoon','ASIN');
insert into testproduct (id,prod_name,productidtype) values ('D12395N5PF','and there we go','ASIN');

全文搜索需要一些多样性来消除重复的噪音".使用最少的数据进行测试将产生较差的结果.把你的整个收藏扔在它上面，以获得任何有意义的东西.甚至尝试搜索的单词的最小大小也有设置，如下面的一些链接所示.

Full Text Search needs some variety to rid itself of repeat 'noise'. Testing with minimal data will yield poor results. Throw your whole collection at it for anything meaningful to come out. There are settings for minimum size of words even attempted to be searched as seen in some links below.

有 MySql 停用词列表在各种语言中表示在搜索过程中跳过的无关紧要的词.该列表被编译到服务器中，但可以被覆盖，如下所示 手册页和文字:

There are MySql Lists of Stop Words in various languages representing insignificant words skipped during the search process. That list is compiled into the server, but can be overriden as seen in this Manual Page and text:

要覆盖默认停用词列表，请设置 ft_stopword_file 系统多变的.(请参阅第 5.1.4 节，服务器系统变量".)变量值应该是包含停用词的文件的路径名列表或空字符串以禁用停用词过滤.服务器除非绝对路径名，否则在数据目录中查找文件指定不同的目录.更改值后这个变量或者停用词文件的内容，重启服务器并重建您的 FULLTEXT 索引.

To override the default stopword list, set the ft_stopword_file system variable. (See Section 5.1.4, "Server System Variables".) The variable value should be the path name of the file containing the stopword list, or the empty string to disable stopword filtering. The server looks for the file in the data directory unless an absolute path name is given to specify a different directory. After changing the value of this variable or the contents of the stopword file, restart the server and rebuild your FULLTEXT indexes.

一些示例查询

-- select * from testproduct
SELECT * FROM testproduct WHERE MATCH(prod_name) AGAINST('score' IN BOOLEAN MODE);
SELECT * FROM testproduct WHERE MATCH(prod_name) AGAINST('harpoon' IN BOOLEAN MODE);
SELECT * FROM testproduct WHERE MATCH(prod_name) AGAINST('banana' IN BOOLEAN MODE);
SELECT * FROM testproduct WHERE MATCH(prod_name) AGAINST('years' IN BOOLEAN MODE);

获取多个单词匹配:

SELECT id,prod_name, match( prod_name )
AGAINST ( '+harpoon +article' IN BOOLEAN MODE ) AS relevance
FROM testproduct 
ORDER BY relevance DESC

在 relevance 列中给出实际权重:

Gives a real weight in relevance column:

SELECT id,prod_name, match( prod_name )
AGAINST ( '+harpoon +article' IN NATURAL LANGUAGE MODE) AS relevance
FROM testproduct 
ORDER BY relevance DESC
+------------+--------------------------------------------------------------------------------------------------------------------+--------------------+
| id         | prod_name                                                                                                          | relevance          |
+------------+--------------------------------------------------------------------------------------------------------------------+--------------------+
| D34595N5PF | this article about harpoons really drills into the throwing of harpoon or harpoons to those that deserve a harpoon | 3.6207125186920166 |
| EEEZZ5N5PF | he has a harpoon                                                                                                   | 1.2845110893249512 |
| C04K95N5PF | threw some daggers and a harpoon                                                                                   | 1.2559525966644287 |
|------------+--------------------------------------------------------------------------------------------------------------------+--------------------+

从此处取消了多词部分.谢谢斯宾塞

Lifted the multiple words section from here. Thanks spencer

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