mysql学习--mysql必知必会1



例如以下为mysql必知必会第九章開始：

正則表達式用于匹配特殊的字符集合。mysql通过where子句对正則表達式提供初步的支持。

keywordregexp用来表示后面跟的东西作为正則表達式处理。

（.）是正則表達式的一个符号，表示匹配随意一个字符：

mysql> select prod_name
    -> from products
    -> where prod_name regexp '.000'
    -> order by prod_name;
+--------------+
| prod_name    |
+--------------+
| JetPack 1000 |
| JetPack 2000 |
+--------------+
2 rows in set (0.14 sec)

|匹配符：

表示匹配当中之中的一个

mysql> select prod_name
    -> from products
    -> where prod_name REGEXP '1000|2000'
    -> ORDER BY prod_name;
+--------------+
| prod_name    |
+--------------+
| JetPack 1000 |
| JetPack 2000 |
+--------------+
2 rows in set (0.00 sec)

[]匹配符： 匹配几个字符之中的一个

2 rows in set (0.00 sec)

mysql> select prod_name
    -> from products
    -> where prod_name regexp '[123] Ton'
    -> ;
+-------------+
| prod_name   |
+-------------+
| 1 ton anvil |
| 2 ton anvil |
+-------------+
2 rows in set (0.00 sec)

mysql> select prod_name from products where prod_name regexp '[1-5] Ton';
+--------------+
| prod_name    |
+--------------+
| .5 ton anvil |
| 1 ton anvil  |
| 2 ton anvil  |
+--------------+
3 rows in set (0.02 sec)

(^)否定匹配符：

mysql> select prod_name from products where prod_name regexp '[^1-3] Ton';
+--------------+
| prod_name    |
+--------------+
| .5 ton anvil |
+--------------+
1 row in set (0.00 sec)

匹配特殊字符，必须用\\为前导。

mysql> select prod_name from products where prod_name regexp '\\.' ;
+--------------+
| prod_name    |
+--------------+
| .5 ton anvil |
+--------------+
1 row in set (0.00 sec)

匹配字符类：

mysql> select prod_name from products where prod_name REGEXP '\\([0-9] sticks?\\)' order by prod_name;
+----------------+
| prod_name      |
+----------------+
| TNT (1 stick)  |
| TNT (5 sticks) |
+----------------+
2 rows in set (0.05 sec)

mysql> select prod_name from products where prod_name REGEXP '[[:digit:]]{4}' order by prod_name;
+--------------+
| prod_name    |
+--------------+
| JetPack 1000 |
| JetPack 2000 |
+--------------+
2 rows in set (0.00 sec)

定位符使用方法：

mysql> select prod_name
    -> from products
    -> where prod_name REGEXP '^[0-9\\.]'
    -> order by prod_name;
+--------------+
| prod_name    |
+--------------+
| .5 ton anvil |
| 1 ton anvil  |
| 2 ton anvil  |
+--------------+
3 rows in set (0.00 sec)

以上都是mysql正則表達式的使用方法。