49 lines
1.1 KiB
Markdown
49 lines
1.1 KiB
Markdown
# 删除数据
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> mysql删除是使用delete语句
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## delete
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删除语法其实是非常简单的，但是也是比较危险的，需要慎重操作。
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```sql
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delete from table [where ];
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```
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最简单的删除语句是
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```sql
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delete from tablename;
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```
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但是不要这么操作，他会像修改时候一样，全部删除掉，所以操作删除的时候一定要添加条件
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```sql
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delete from tablename where 条件;
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```
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还是之前的class表。
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比如我要删除姓名为张三的人，应该怎么删除呢？
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```sql
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delete from class where name = "张三";
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```
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删除成功了，然后查询之后张三就没有了。
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比如要删除年龄是18的人，那么应该就是 `where age = 18`
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```sql
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delete from class where age = 18;
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```
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成功删除了，删除了所有年龄是18的人。
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删除是比较简单的操作，接下来就要来看一下主键。 |