SQL delete 语句,删除表数据

SQL DELETE 语句

DELETE 语句用于删除表中的行。

SQL DELETE 语法

DELETE FROM table_name WHERE some_column=some_value;

请注意 SQL DELETE 语句中的 WHERE 子句! WHERE 子句规定哪条记录或者哪些记录需要删除。如果您省略了 WHERE 子句,所有的记录都将被删除!

实例

实例表

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 3  | Facebook     | https://www.facebook.com/ | 3     | USA     |
| 4  | 百度     | https://www.baidu.com/ | 4     | CN     |
+----+--------------+---------------------------+-------+---------+

删除facebook

DELETE FROM Websites
WHERE name='Facebook' AND country='USA';

结果:

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 4  | 百度     | https://www.baidu.com/ | 4     | CN     |
+----+--------------+---------------------------+-------+---------+

删除所有数据

您可以在不删除表的情况下,删除表中所有的行。这意味着表结构、属性、索引将保持不变:

DELETE FROM table_name;

注释:在删除记录时要格外小心!因为您不能重来!