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MySQL更新和删除

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Release： 2016-06-07 16:22:02
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更新和删除的操作SQL语句比较简单，不过要注意使用UPDATE的时候，要注意WEHER条件的限制，下面的语句是只更新id为10005的email地址，如果不加WHERE语句限制，那么将表中所有的email更新为 elmer@fudd.com： 删除某个列的值，设置为NULL即可。 删除行的SQL语

 　　更新和删除的操作SQL语句比较简单，不过要注意使用UPDATE的时候，要注意WEHER条件的限制，下面的语句是只更新id为10005的email地址，，如果不加WHERE语句限制，那么将表中所有的email更新为 elmer@fudd.com：

MySQL更新和删除 三联

　　删除某个列的值，设置为NULL即可。

MySQL更新和删除

　　删除行的SQL语句，使用DELETE，使用DELETE时同样要加WHERE删除你想要删除的行，不指定的话，会删除该表中所有的行。

　　DELETE FROM customers

　　WHERE cust_id =10005;

　　至此我们也看出，一个表中，其主键的重要性了。另外在UPDATE和DELETE前，可以先使用SELECT语句来测试WHERE语句所限定的条件是否是正确的。

Related labels：
mysql delete
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