5.MySQL数据库之排序检索数据

迷南。 2023-06-17 13:58 24阅读 0赞

## MySQL数据库之排序检索数据 ##

数据库：own  ->>表：single\_pro

**1.根据某列排列**

关键点：使用order by  列名即可。

语法：select \[列\]  from \[表\]  order by \[列名\]

【默认升序排列】

如果遇中文，改为order by convert(列名 using gbk)

示例：

select * from single_pro order by downloadcount limit 10;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70][]

**2.根据某些列排序**

关键点：以逗号分隔需要被排列的列。

语法：select \[列\]  from \[表\]  order by \[列名1, 列名2, ...\];

注意点：根据某些列排列的时候，只有当第一列相同时，才会根据第二列进行排列。

示例：根据downloadcount和counted两列进行升序排列。

select downloadcount,counted from single_pro order by downloadcount, counted limit 200;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 1][]

**3.指定排序方向**

关键点：order by默认升序(0-1,a-z,A-Z),所以想降序的话，需要使用desc关键字

语法：select \[列\]  from \[表\]  order by \[列\]  desc;

示例：根据downloadcount这一列进行降序排列.

select * from single_pro order by downloadcount desc limit 20 ;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 2][]

**4.根据多列降序**

根据counted降序排列，当counted相同时，根据downloadcount升序排列。【desc仅作用于其前面的一列】

select downloadcount,counted from single_pro order by counted desc,downloadcount limit 20;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 3][]

select downloadcount,counted from single_pro order by counted desc,downloadcount desc limit 20;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjgzMDY5Nw_size_16_color_FFFFFF_t_70 4][]

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