MySQL fulltext index检索中文有哪些注意事项

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1、查看表结构

mysql> show create table product_test02;| Table                | Create Table   | product_test02 | CREATE TABLE `product_test02` (  `product_id` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL,  `artisan_id` varchar(40) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `name` varchar(60) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',  `des` varchar(1000) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL DEFAULT '',  `zhima_price` double(11,2) DEFAULT NULL,  `market_price` double(11,2) DEFAULT NULL,  `cover_pic` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `work_time` int(11) DEFAULT NULL,  `comment_count` int(11) DEFAULT NULL,  `like_count` int(11) DEFAULT NULL,  `produt_consist` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `keep_time` int(11) DEFAULT NULL,  `create_at` timestamp NULL DEFAULT NULL,  `fav_count` int(11) DEFAULT NULL,  `width` int(11) DEFAULT NULL,  `height` int(11) DEFAULT NULL,  `is_publish` int(11) DEFAULT NULL,  `is_top` int(11) DEFAULT NULL,  `is_delete` int(11) DEFAULT NULL,  `sell_amount` int(11) DEFAULT '0',  `free_service_time` int(11) DEFAULT NULL,  `update_time` timestamp NULL DEFAULT NULL,  `other_1` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `other_2` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `other_3` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `other_4` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `other_5` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `is_audit` tinyint(1) DEFAULT '0',  `audit_time` timestamp NULL DEFAULT NULL,  `is_undercarriage` tinyint(1) DEFAULT '0',  `undercarriage_time` timestamp NULL DEFAULT NULL,  `category` varchar(30) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',  `active_tag_dict_id` bigint(20) DEFAULT NULL,  `active_price` double(11,1) DEFAULT NULL,  `weight` int(11) unsigned DEFAULT '0',  `fit_people` varchar(300) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `matter_attent` varchar(800) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,  `category_lv2_id` int(11) DEFAULT NULL,  `artisan_visit` int(1) DEFAULT '1',  `customer_visit` int(1) DEFAULT '0',  `customer_zhima_price` double(11,2) DEFAULT NULL,  `customer_market_price` double(11,2) DEFAULT NULL,  `service_sex` int(1) DEFAULT '0',  `service_mode` tinyint(2) DEFAULT '0' ,  `last_update_time` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,  `sell_price` double(11,2) NOT NULL DEFAULT '0.00',  `is_new` int(1) NOT NULL,  `spu_id` int(11) DEFAULT NULL,  `category_id` int(11) DEFAULT NULL,  `other_info` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',  `product_type` int(2) NOT NULL DEFAULT '0' ,  `product_code` varchar(15) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2、在name字段创建fulltext索引

mysql> alter table product_test02 add FULLTEXT index ft_indx_name (name) WITH PARSER ngram;Query OK, 0 rows affected, 1 warning (3 min 45.93 sec)

3、利用fulltext index进行检索

mysql> select name from product_test02 where match(name) against ('头部' in boolean mode) limit 1;+---------------------+| name                |+---------------------+| 头部按*摩+拨筋       |+---------------------+1 row in set (0.00 sec)

mysql> select name from product_test02 where match(name) against ('头' in boolean mode) limit 1;Empty set (0.00 sec)

经查询：这个是数据库ft_min_word_len参数有关，默认为4，至少检索4个字符，被检索字符串长度小于4个字符将检索不到。

4、改参数ft_min_word_len = 1并重启实例

mysql> show variables like 'ft%';+--------------------------+----------------+| Variable_name            | Value          |+--------------------------+----------------+| ft_boolean_syntax        | + -><()~*:""&| || ft_max_word_len          | 84             || ft_min_word_len          | 1              || ft_query_expansion_limit | 20             || ft_stopword_file         | (built-in)     |+--------------------------+----------------+

5、再次查询

mysql> select name from product_test02 where match(name) against ('头' in boolean mode) limit 1;Empty set (0.01 sec)

依然查询不到，原因是ft_min_word_len 参数改完之后，必须重建所有fulltext index

6、重建fulltext index并检索

mysql> select name from product_test02 where match(name) against ('头部' in boolean mode) limit 1;Empty set (0.00 sec)mysql> select name from product_test02 where match(name) against ('3' in boolean mode) limit 1;Empty set (0.00 sec)

经查询，ngram_token_size=2 #用中文检索分词插件ngram之前，先得在MySQL配置文件里面设置他的分词大小

7、更改参数ngram_token_size=1，并重启实例

mysql> show variables like 'ng%';+------------------+-------+| Variable_name    | Value |+------------------+-------+| ngram_token_size | 1     |+------------------+-------+1 row in set (0.01 sec)mysql> select name from product_test02 where match(name) against ('头部' in boolean mode) limit 1;+---------------------------------------------+| name                                        |+---------------------------------------------+| 【头疼必拍】头部舒压+经络疏通               |+---------------------------------------------+1 row in set (0.01 sec)mysql> select name from product_test02 where match(name) against ('头' in boolean mode) limit 1;+--------------------------------------------------+| name                                             |+--------------------------------------------------+| 头部拨筋头晕头痛失眠【头部调理】                 |+--------------------------------------------------+1 row in set (0.01 sec)

可以正常检索。

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