MySQL学习足迹记录06--数据过滤--LIKE搭配百分号（%）和下划线（_）通配符

1.LIKE操作符


*%表示匹配任何字符出现任意次数（>=0)

[b] 为了便于观察，先把prod_name字段的所有的数据列出[/b]

eg:

mysql> SELECT prod_name FROM products;

+----------------+

| prod_name |

+----------------+

| .5 ton anvil |

| 1 ton anvil |

| 2 ton anvil |

| Detonator |

| Bird seed |

| Carrots |

| Fuses |

| JetPack 1000 |

| JetPack 2000 |

| Oil can |

| Safe |

| Sling |

| TNT (1 stick) |

| TNT (5 sticks) |

+----------------+

14 rows in set (0.00 sec)



mysql> SELECT prod_name FROM products

-> WHERE prod_name LIKE 'jet%'; #检索一任何"jet"开头的数据

+--------------+

| prod_name |

+--------------+

| JetPack 1000 |

| JetPack 2000 |

+--------------+

2 rows in set (0.00 sec)

mysql> SELECT prod_name FROM products

-> WHERE prod_name LIKE '%anvil%';

#'%anvil%'表示匹配任何位置包含文本anvil的值

+--------------+

| prod_name |

+--------------+

| .5 ton anvil |

| 1 ton anvil |

| 2 ton anvil |

+--------------+

3 rows in set (0.00 sec)

mysql> SELECT prod_name FROM products

-> WHERE prod_name LIKE 's%e';

#找出以s开头并一e结尾的所有产品

+-----------+

| prod_name |

+-----------+

| Safe |

+-----------+

1 row in set (0.00 sec)

*下划线（_)通配符

用途与%一样，但下划线只匹配单个字符

eg:

mysql> SELECT prod_name FROM products

-> WHERE prod_name LIKE '_ ton anvil';

+-------------+

| prod_name |

+-------------+

| 1 ton anvil |

| 2 ton anvil |

+-------------+

2 rows in set (0.01 sec)



请对比%操作符的结果：

mysql> SELECT prod_name FROM products

-> WHERE prod_name LIKE '% ton anvil';

+--------------+

| prod_name |

+--------------+

| .5 ton anvil |

| 1 ton anvil |

| 2 ton anvil |

+--------------+

3 rows in set (0.00 sec)