[4]SQL AND & OR

Posted 2020-10-13

[4]SQL AND & OR 

下面是选自 "Websites" 表的数据：

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 3  | 菜鸟教程      | http://www.runoob.com/    | 4689  | CN      |
| 4  | 微博          | http://weibo.com/         | 20    | CN      |
| 5  | Facebook     | https://www.facebook.com/ | 3     | USA     |

实例

SELECT * FROM Websites
WHERE country=‘CN‘
AND alexa > 50;

执行输出结果：

实例

SELECT * FROM Websites
WHERE country=‘USA‘
OR country=‘CN‘;

执行输出结果：

实例

SELECT * FROM Websites
WHERE alexa > 15
AND (country=‘CN‘ OR country=‘USA‘);

执行输出结果：