MySQL全面瓦解8：查詢的正則匹配

翁智華發表於2020-11-10
MySql

概述

上一章 查詢的過濾條件，我們瞭解了MySQL可以通過 like % 萬用字元來進行模糊匹配。同樣的，它也支援其他正規表示式的匹配，我們在MySQL中使用 REGEXP 操作符來進行正規表示式匹配。用法和like相

似，但又強大很多，能夠實現一些很特殊的、複雜的規則匹配。正規表示式使用REGEXP命令進行匹配時，如果符合返回1，不符合返回0。如果 預設不加任何匹配規則REGEXP相當於like '%%'。在前面加上NOT（NOT REGEXP）相當於NOT LIKE。

匹配模式分析

下面有個表格 ，羅列了可應用於 REGEXP 操作符中正則匹配模式，描述相對比較詳細了，後面我們一個一個來測試。

匹配模式

描述

^

匹配輸入字串的開始位置。如果設定了 REGEXP 物件的 Multiline 屬性，^ 也匹配 '\n' 或 '\r' 之後的位置。

$

匹配輸入字串的結束位置。如果設定了REGEXP 物件的 Multiline 屬性，$ 也匹配 '\n' 或 '\r' 之前的位置。

.

匹配除 "\n" 之外的任何單個字元。要匹配包括 '\n' 在內的任何字元，請使用 '[.\n]' 的模式。

[….]

字符集合。匹配所包含的任意一個字元。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元。例如， '[^abc]' 可以匹配 "plain" 中的'p'。

[n-m]

匹配m到n之間的任意單個字元，例如[0-9],[a-z],[A-Z]

*

匹配前面的子表示式零次或多次。例如，a* 能匹配 "a" 以及 "ab"。* 等價於{0,}。

+

匹配前面的子表示式一次或多次。例如，'a+' 能匹配 "ab" 以及 "abc"，但不能匹配 "a"。+ 等價於 {1,}。

?

匹配前面的子表示式一次或多次。例如，'a?' 能匹配 "ab" 以及 "a"。? 等價於 {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' 則匹配 "zood" 或 "food"。

{n}

n 是一個非負整數。匹配確定的 n 次。例如，'o{2}' 不能匹配 "Bob" 中的 'o'，但是能匹配 "food" 中的兩個 o。

{n,}

匹配前面的子表示式n次到多次。例如，'o{2,}' 不僅能匹配 "food" ，也能匹配 "foood"。

{n,m}

n 和 m 均為非負整數，其中n <= m。最少匹配 n 次且最多匹配 m 次。

{,m}

匹配前面的子表示式0次到m次

(….)

元素組合，即將模式元素組成單一元素，例如（do）*意思是匹配0個多或多個do

 

匹配模式^

從字串首部分進行匹配，這邊匹配s開頭的，匹配符合返回1，不符合返回0。應用到表中，既符合返回匹配到的資料。

 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$

從字串尾部進行匹配，這邊匹配名稱以d結尾的資料。

 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.

. 是匹配任意單個字元，下面指令碼匹配 n並且後面帶一個任意字元的條件

 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[...]

指匹配括號內的任意單個字元，只要有一個字元符合條件即可。下面例子能匹配到b、w、z的 只有brand、weng 兩個名稱。

 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元。例如， '[^brand]' 可以匹配 "helen" 中的'h'，"sol" 的 "s"，"weng" 的 "w"，"selina" 的 "s"，但無法匹配"brand"，所以被過濾了。

 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之間的任意單個字元，例如[0-9],[a-z],[A-Z]，下方程式碼中，任何元素不在a - e之間的"sol" 被過濾了。

 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 *

匹配前面的子表示式零次或多次。例如，a* 能匹配 "a" 以及 "ab"。* 等價於{0,}。 下面的 "e*g" 可以匹配的只有 "weng" 這個名稱。 
 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 +

匹配前面的子表示式一次或多次。例如，'a+' 能匹配 "ab" 以及 "abc"，但不能匹配 "a"。+ 等價於 {1,}。如下方的指令碼，符合條件的是1到多個的n加上一個d的組合，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 ?

匹配前面的子表示式一次或多次。例如，'a?' 能匹配 "ab" 以及 "a"。? 等價於 {0,1}。e為1個或者0個，後面再用 l 限制，所以符合的只有三個。

 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' 能分別匹配到 "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 均為非負整數，其中n <= m。最少匹配 n 次且最多匹配 m 次。m為空代表>=n的任意數，n為空代表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(...) 

假設括號內容為abc，則是將abc作為一個整體去匹配，符合這個規則的資料被過濾出來。下面以an為例子，配合上面學過的知識。

 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

匹配特殊字元 \\

正規表示式語言由具有特定含義的特殊字元構成。我們已經看到.、 []、|、*、+ 等， 那我們是怎麼匹配這些字元的。如下示例，我們使用 \\ 來匹配特殊字元，\\為前導， \\-表示查詢-， \\.表示查詢.。 

 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 

總結

1.當我們需要用正則匹配資料的時候，可以使用REGEXP和NOT REGEXP操作符(類似LIKE和NOT LIKE)；

2.REGEXP預設不區分大小寫，可以使用BINARY關鍵詞強制區分大小寫； WHERE NAME REGEXP BINARY ‘^[A-Z]’;

3.REGEXP預設是部分匹配原則，即有一個匹配上則返回真。例如：SELECT  'A123' REGEXP BINARY '[A-Z]'，返回的是1;

4、如果使用 () 進行匹配，則是將括號內部的內容當作整體去匹配，比如 (ABC)，則需要匹配整個ABC。

5、這邊只是看介紹了正則的基礎知識，想要更為透徹的瞭解可以參考 正則教程 ，我覺得寫的不錯。

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