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。

1 mysql> select 'selina' REGEXP '^s'; 2 +----------------------+ 3 | 'selina' REGEXP '^s' | 4 +----------------------+ 5 | 1 | 6 +----------------------+ 7 1 row in set 8 9 mysql> select 'aelina' REGEXP '^s';10 +----------------------+11 | 'aelina' REGEXP '^s' |12 +----------------------+13 | 0 |14 +----------------------+15 1 row in set 1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP '^s';14 +----+--------+-----+---------+-----+15 | id | name | age | address | sex |16 +----+--------+-----+---------+-----+17 | 3 | sol | 21 | xiamen | 0 |18 | 5 | selina | 25 | NULL | 0 |19 +----+--------+-----+---------+-----+20 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP 'd$';14 +----+-------+-----+---------+-----+15 | id | name | age | address | sex |16 +----+-------+-----+---------+-----+17 | 1 | brand | 21 | fuzhou | 1 |18 +----+-------+-----+---------+-----+19 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

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP 'n.';14 +----+--------+-----+---------+-----+15 | id | name | age | address | sex |16 +----+--------+-----+---------+-----+17 | 1 | brand | 21 | fuzhou | 1 |18 | 4 | weng | 33 | guizhou | 1 |19 | 5 | selina | 25 | NULL | 0 |20 +----+--------+-----+---------+-----+21 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP [bwz];14 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 115 mysql> select * from user2 where name REGEXP '[bwz]';16 +----+-------+-----+---------+-----+17 | id | name | age | address | sex |18 +----+-------+-----+---------+-----+19 | 1 | brand | 21 | fuzhou | 1 |20 | 4 | weng | 33 | guizhou | 1 |21 +----+-------+-----+---------+-----+22 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP '[^brand]';14 +----+--------+-----+----------+-----+15 | id | name | age | address | sex |16 +----+--------+-----+----------+-----+17 | 2 | helen | 20 | quanzhou | 0 |18 | 3 | sol | 21 | xiamen | 0 |19 | 4 | weng | 33 | guizhou | 1 |20 | 5 | selina | 25 | NULL | 0 |21 +----+--------+-----+----------+-----+22 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP '[a-e]';14 +----+--------+-----+----------+-----+15 | id | name | age | address | sex |16 +----+--------+-----+----------+-----+17 | 1 | brand | 21 | fuzhou | 1 |18 | 2 | helen | 20 | quanzhou | 0 |19 | 4 | weng | 33 | guizhou | 1 |20 | 5 | selina | 25 | NULL | 0 |21 +----+--------+-----+----------+-----+22 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 +----+--------+-----+----------+-----+11 5 rows in set12 13 mysql> select * from user2 where name REGEXP 'e*g';14 +----+------+-----+---------+-----+15 | id | name | age | address | sex |16 +----+------+-----+---------+-----+17 | 4 | weng | 33 | guizhou | 1 |18 +----+------+-----+---------+-----+19 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 | 6 | anny | 23 | shanghai | 0 |11 | 7 | annd | 24 | shanghai | 1 |12 +----+--------+-----+----------+-----+13 7 rows in set14 15 mysql> select * from user2 where name REGEXP 'n+d';16 +----+-------+-----+----------+-----+17 | id | name | age | address | sex |18 +----+-------+-----+----------+-----+19 | 1 | brand | 21 | fuzhou | 1 |20 | 7 | annd | 24 | shanghai | 1 |21 +----+-------+-----+----------+-----+22 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 | 6 | anny | 23 | shanghai | 0 |11 | 7 | annd | 24 | shanghai | 1 |12 +----+--------+-----+----------+-----+13 7 rows in set14 15 mysql> select * from user2 where name REGEXP 'e?l';16 +----+--------+-----+----------+-----+17 | id | name | age | address | sex |18 +----+--------+-----+----------+-----+19 | 2 | helen | 20 | quanzhou | 0 |20 | 3 | sol | 21 | xiamen | 0 |21 | 5 | selina | 25 | NULL | 0 |22 +----+--------+-----+----------+-----+23 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"。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 | 6 | anny | 23 | shanghai | 0 |11 | 7 | annd | 24 | shanghai | 1 |12 +----+--------+-----+----------+-----+13 7 rows in set14 15 mysql> select * from user2 where name REGEXP 'nn|en';16 +----+-------+-----+----------+-----+17 | id | name | age | address | sex |18 +----+-------+-----+----------+-----+19 | 2 | helen | 20 | quanzhou | 0 |20 | 4 | weng | 33 | guizhou | 1 |21 | 6 | anny | 23 | shanghai | 0 |22 | 7 | annd | 24 | shanghai | 1 |23 +----+-------+-----+----------+-----+24 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 | 6 | anny | 23 | shanghai | 0 |11 | 7 | annd | 24 | shanghai | 1 |12 +----+--------+-----+----------+-----+13 7 rows in set14 15 mysql> select * from user2 where name REGEXP 'n{2}';16 +----+------+-----+----------+-----+17 | id | name | age | address | sex |18 +----+------+-----+----------+-----+19 | 6 | anny | 23 | shanghai | 0 |20 | 7 | annd | 24 | shanghai | 1 |21 +----+------+-----+----------+-----+22 2 rows in set23 24 mysql> select * from user2 where name REGEXP 'n{1,2}';25 +----+--------+-----+----------+-----+26 | id | name | age | address | sex |27 +----+--------+-----+----------+-----+28 | 1 | brand | 21 | fuzhou | 1 |29 | 2 | helen | 20 | quanzhou | 0 |30 | 4 | weng | 33 | guizhou | 1 |31 | 5 | selina | 25 | NULL | 0 |32 | 6 | anny | 23 | shanghai | 0 |33 | 7 | annd | 24 | shanghai | 1 |34 +----+--------+-----+----------+-----+35 6 rows in set36 37 mysql> select * from user2 where name REGEXP 'l{1,}';38 +----+--------+-----+----------+-----+39 | id | name | age | address | sex |40 +----+--------+-----+----------+-----+41 | 2 | helen | 20 | quanzhou | 0 |42 | 3 | sol | 21 | xiamen | 0 |43 | 5 | selina | 25 | NULL | 0 |44 +----+--------+-----+----------+-----+45 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。

1 mysql> select * from user2; 2 +----+--------+-----+----------+-----+ 3 | id | name | age | address | sex | 4 +----+--------+-----+----------+-----+ 5 | 1 | brand | 21 | fuzhou | 1 | 6 | 2 | helen | 20 | quanzhou | 0 | 7 | 3 | sol | 21 | xiamen | 0 | 8 | 4 | weng | 33 | guizhou | 1 | 9 | 5 | selina | 25 | NULL | 0 |10 | 6 | anny | 23 | shanghai | 0 |11 | 7 | annd | 24 | shanghai | 1 |12 +----+--------+-----+----------+-----+13 7 rows in set14 15 mysql> select * from user2 where name REGEXP '(an)+';16 +----+-------+-----+----------+-----+17 | id | name | age | address | sex |18 +----+-------+-----+----------+-----+19 | 1 | brand | 21 | fuzhou | 1 |20 | 6 | anny | 23 | shanghai | 0 |21 | 7 | annd | 24 | shanghai | 1 |22 +----+-------+-----+----------+-----+23 3 rows in set24 25 mysql> select * from user2 where name REGEXP '(ann)+';26 +----+------+-----+----------+-----+27 | id | name | age | address | sex |28 +----+------+-----+----------+-----+29 | 6 | anny | 23 | shanghai | 0 |30 | 7 | annd | 24 | shanghai | 1 |31 +----+------+-----+----------+-----+32 2 rows in set33 34 mysql> select * from user2 where name REGEXP '(an).*d{1,2}';35 +----+-------+-----+----------+-----+36 | id | name | age | address | sex |37 +----+-------+-----+----------+-----+38 | 1 | brand | 21 | fuzhou | 1 |39 | 7 | annd | 24 | shanghai | 1 |40 +----+-------+-----+----------+-----+41 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.。

1 mysql> select * from user3; 2 +----+------+-------+ 3 | id | age | name | 4 +----+------+-------+ 5 | 1 | 20 | brand | 6 | 2 | 22 | sol | 7 | 3 | 20 | helen | 8 | 4 | 19.5 | diny | 9 +----+------+-------+10 4 rows in set11 12 mysql> select * from user3 where age REGEXP '[0-9]+\\.[0-9]+';13 +----+------+------+14 | id | age | name |15 +----+------+------+16 | 4 | 19.5 | diny |17 +----+------+------+18 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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