三、基础查询——MySQL数据库之排序(6)

以你之姓@ 2023-06-21 15:23 114阅读 0赞

## 三、基础查询——MySQL数据库之排序(6) ##

### 1.什么是排序 ###

简单来讲，就是将查询到的数据根据一定条件进行排序。比如，检索出来的水果价格均大于10元，然后对价格从小到大或者从大到小进行排序。

### 2.语法 ###

升序排列：asc 【默认】

降序排列：desc

select [列名1,列名2,...] from 表 
    where 条件表达式
    order by 列名[asc/desc];

### 3.升序排列\[单列\] ###

**示例1：**

描述：将检索出来的价格大于10的数据升序排列。注意，asc可以省略不写。

select * from fruit where price>10 order by price asc;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70][]

**示例2：**

描述：将检索出来的数据根据num升序排列。

select * from fruit where price>10 order by num;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 1][]

### 4.降序排列【单列】 ###

**示例1：**

描述：将检索出来的价格大于10的数据降序排列。注意，desc必须写。

select * from fruit where price>10 order by price desc;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 2][]

**示例2：**

描述：将检索出来的数据根据num降序排列。

select * from fruit where price>10 order by num desc;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 3][]

### 5.多列排序 ###

**示例1：**

根据num和price升序排列。

select * from fruit where price>10 order by num,price;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 4][]

**示例2：**

根据num列升序，price列降序。

select * from fruit where price>10 order by num,price desc;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 5][]

### 6.注意事项 ###

(1)排序时，asc与desc关键字必须跟在被排序的列的后面。

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