MySQL全面瓦解8:查询的正则匹配

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MySQL全面瓦解8:查询的正则匹配

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

描述

^

匹配输入字符串的开始位置。如果设置了 REGEXP 对象的 Multiline 属性,^ 也匹配 ‘\n’ 或 ‘\r’ 之后的位置。

$

匹配输入字符串的结束位置。如果设置了REGEXP 对象的 Multiline 属性,$ 也匹配 ‘\n’ 或 ‘\r’ 之前的位置。

.

匹配除 “\n” 之外的任何单个字符。要匹配包括 ‘\n’ 在内的任何字符,请使用 ‘[.\n]’ 的模式。

[….]

字符集合。匹配所包含的任意一个字符。例如, ‘[abc]’ 可以匹配 “plain” 中的 ‘a’。

[^…]

非匹配字符集合。匹配未包含的任意字符。例如, ‘[^abc]’ 可以匹配 “plain” 中的’p’。

[n-m]

匹配m到n之间的任意单个字符,例如[0-9],[a-z],[A-Z]

*

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,}。

+

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,}。

?

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}。

a1| a2|a3

匹配 a1 或 a2 或 a3。例如,’z|food’ 能匹配 “z” 或 “food”。'(z|f)ood’ 则匹配 “zood” 或 “food”。

{n}

n 是一个非负整数。匹配确定的 n 次。例如,’o{2}’ 不能匹配 “Bob” 中的 ‘o’,但是能匹配 “food” 中的两个 o。

{n,}

匹配前面的子表达式n次到多次。例如,’o{2,}’ 不仅能匹配 “food” ,也能匹配 “foood”。

{n,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}

匹配前面的子表达式0次到m次

(….)

元素组合,即将模式元素组成单一元素,例如(do)*意思是匹配0个多或多个do

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 set
12
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 set
12
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 set
12
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 set
12
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 1
15 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 set
12
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 set
12
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 *

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 set
12
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 set
14
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 set
14
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 set
14
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 set
14
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 set
23
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 set
36
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 set
14
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 set
24
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 set
33
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 set
11
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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