MySQL全面瓦解之查询的正则匹配详解

概述

上一章 查询的过滤条件，我们了解了MySQL可以通过 like % 通配符来进行模糊匹配。同样的，它也支持其他正则表达式的匹配，我们在MySQL中使用 REGEXP 操作符来进行正则表达式匹配。用法和like相

似，但又强大很多，能够实现一些很特殊的、复杂的规则匹配。正则表达式使用REGEXP命令进行匹配时，如果符合返回1，不符合返回0。如果 默认不加任何匹配规则REGEXP相当于like \’%%\’。在前面加上NOT（NOT REGEXP）相当于NOT LIKE。

匹配模式分析

下面有个表格 ，罗列了可应用于 REGEXP 操作符中正则匹配模式，描述相对比较详细了，后面我们一个一个来测试。

匹配模式^

从字符串首部分进行匹配，这边匹配s开头的，匹配符合返回1，不符合返回0。应用到表中，既符合返回匹配到的数据。

mysql> select \'selina\' REGEXP \'^s\';+----------------------+| \'selina\' REGEXP \'^s\' |+----------------------+|   1 |+----------------------+1 row in setmysql> select \'aelina\' REGEXP \'^s\';+----------------------+| \'aelina\' REGEXP \'^s\' |+----------------------+|   0 |+----------------------+1 row in set

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'^s\';+----+--------+-----+---------+-----+| id | name | age | address | sex |+----+--------+-----+---------+-----+| 3 | sol | 21 | xiamen | 0 || 5 | selina | 25 | NULL | 0 |+----+--------+-----+---------+-----+2 rows in set

匹配模式$

从字符串尾部进行匹配，这边匹配名称以d结尾的数据。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'d$\';+----+-------+-----+---------+-----+| id | name | age | address | sex |+----+-------+-----+---------+-----+| 1 | brand | 21 | fuzhou | 1 |+----+-------+-----+---------+-----+1 row in set

匹配模式.

. 是匹配任意单个字符，下面脚本匹配 n并且后面带一个任意字符的条件

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'n.\';+----+--------+-----+---------+-----+| id | name | age | address | sex |+----+--------+-----+---------+-----+| 1 | brand | 21 | fuzhou | 1 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL | 0 |+----+--------+-----+---------+-----+3 rows in set

匹配模式[…]

指匹配括号内的任意单个字符，只要有一个字符符合条件即可。下面例子能匹配到b、w、z的 只有brand、weng 两个名称。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP [bwz];1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near \'[bwz]\' at line 1mysql> select * from user2 where name REGEXP \'[bwz]\';+----+-------+-----+---------+-----+| id | name | age | address | sex |+----+-------+-----+---------+-----+| 1 | brand | 21 | fuzhou | 1 || 4 | weng | 33 | guizhou | 1 |+----+-------+-----+---------+-----+2 rows in set

匹配模式[^…]

[^…]取反的意思，指匹配未包含的任意字符。例如， \'[^brand]\’ 可以匹配 \”helen\” 中的\’h\’，\”sol\” 的 \”s\”，\”weng\” 的 \”w\”，\”selina\” 的 \”s\”，但无法匹配\”brand\”，所以被过滤了。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'[^brand]\';+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+4 rows in set

匹配模式[n-m]

匹配m到n之间的任意单个字符，例如[0-9],[a-z],[A-Z]，下方代码中，任何元素不在a – e之间的\”sol\” 被过滤了。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'[a-e]\';+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+4 rows in set

匹配模式 *

匹配前面的子表达式零次或多次。例如，a* 能匹配 \”a\” 以及 \”ab\”。* 等价于{0,}。 下面的 \”e*g\” 可以匹配的只有 \”weng\” 这个名称。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+5 rows in setmysql> select * from user2 where name REGEXP \'e*g\';+----+------+-----+---------+-----+| id | name | age | address | sex |+----+------+-----+---------+-----+| 4 | weng | 33 | guizhou | 1 |+----+------+-----+---------+-----+1 row in set

匹配模式 +

匹配前面的子表达式一次或多次。例如，\’a+\’ 能匹配 \”ab\” 以及 \”abc\”，但不能匹配 \”a\”。+ 等价于 {1,}。如下方的脚本，符合条件的是1到多个的n加上一个d的组合，只有 \”brand\” 和 \”annd\” 符合。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+7 rows in setmysql> select * from user2 where name REGEXP \'n+d\';+----+-------+-----+----------+-----+| id | name | age | address | sex |+----+-------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 7 | annd | 24 | shanghai | 1 |+----+-------+-----+----------+-----+2 rows in set

匹配模式 ?

匹配前面的子表达式一次或多次。例如，\’a?\’ 能匹配 \”ab\” 以及 \”a\”。? 等价于 {0,1}。e为1个或者0个，后面再用 l 限制，所以符合的只有三个。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+7 rows in setmysql> select * from user2 where name REGEXP \'e?l\';+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+3 rows in set

匹配模式 a1| a2|a3

匹配 a1 或 a2 或 a3。例如下方，\’nn|en\’ 能分别匹配到 \”anny\” 、\”annd\” 和 \”helen\”、\”weng\”。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+7 rows in setmysql> select * from user2 where name REGEXP \'nn|en\';+----+-------+-----+----------+-----+| id | name | age | address | sex |+----+-------+-----+----------+-----+| 2 | helen | 20 | quanzhou | 0 || 4 | weng | 33 | guizhou | 1 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+-------+-----+----------+-----+4 rows in set

匹配模式 {n} {n,} {n,m} {,m}

n 和 m 均为非负整数，其中n <= m。最少匹配 n 次且最多匹配 m 次。m为空代表>=n的任意数，n为空代表0。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+7 rows in setmysql> select * from user2 where name REGEXP \'n{2}\';+----+------+-----+----------+-----+| id | name | age | address | sex |+----+------+-----+----------+-----+| 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+------+-----+----------+-----+2 rows in setmysql> select * from user2 where name REGEXP \'n{1,2}\';+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+6 rows in setmysql> select * from user2 where name REGEXP \'l{1,}\';+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 5 | selina | 25 | NULL  | 0 |+----+--------+-----+----------+-----+3 rows in set

匹配模式(…)

假设括号内容为abc，则是将abc作为一个整体去匹配，符合这个规则的数据被过滤出来。下面以an为例子，配合上面学过的知识。

mysql> select * from user2;+----+--------+-----+----------+-----+| id | name | age | address | sex |+----+--------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 2 | helen | 20 | quanzhou | 0 || 3 | sol | 21 | xiamen | 0 || 4 | weng | 33 | guizhou | 1 || 5 | selina | 25 | NULL  | 0 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+--------+-----+----------+-----+7 rows in setmysql> select * from user2 where name REGEXP \'(an)+\';+----+-------+-----+----------+-----+| id | name | age | address | sex |+----+-------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+-------+-----+----------+-----+3 rows in setmysql> select * from user2 where name REGEXP \'(ann)+\';+----+------+-----+----------+-----+| id | name | age | address | sex |+----+------+-----+----------+-----+| 6 | anny | 23 | shanghai | 0 || 7 | annd | 24 | shanghai | 1 |+----+------+-----+----------+-----+2 rows in setmysql> select * from user2 where name REGEXP \'(an).*d{1,2}\';+----+-------+-----+----------+-----+| id | name | age | address | sex |+----+-------+-----+----------+-----+| 1 | brand | 21 | fuzhou | 1 || 7 | annd | 24 | shanghai | 1 |+----+-------+-----+----------+-----+2 rows in set

匹配特殊字符 \\\\

正则表达式语言由具有特定含义的特殊字符构成。我们已经看到.、 []、|、*、+ 等， 那我们是怎么匹配这些字符的。如下示例，我们使用 \\\\ 来匹配特殊字符，\\\\为前导， \\\\-表示查找-， \\\\.表示查找.。

mysql> select * from user3;+----+------+-------+| id | age | name |+----+------+-------+| 1 | 20 | brand || 2 | 22 | sol || 3 | 20 | helen || 4 | 19.5 | diny |+----+------+-------+4 rows in setmysql> select * from user3 where age REGEXP \'[0-9]+\\\\.[0-9]+\';+----+------+------+| id | age | name |+----+------+------+| 4 | 19.5 | diny |+----+------+------+1 row in set

总结

1.当我们需要用正则匹配数据的时候，可以使用REGEXP和NOT REGEXP操作符(类似LIKE和NOT LIKE)；

2.REGEXP默认不区分大小写，可以使用BINARY关键词强制区分大小写； WHERE NAME REGEXP BINARY ‘^[A-Z]\’;

3.REGEXP默认是部分匹配原则，即有一个匹配上则返回真。例如：SELECT \’A123\’ REGEXP BINARY \'[A-Z]\’，返回的是1;

4、如果使用 () 进行匹配，则是将括号内部的内容当作整体去匹配，比如 (ABC)，则需要匹配整个ABC。

5、这边只是看介绍了正则的基础知识，想要更为透彻的了解可以参考 正则教程 ，我觉得写的不错。

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