5.MySQL数据库之排序检索数据
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;
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;
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 ;
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;
select downloadcount,counted from single_pro order by counted desc,downloadcount desc limit 20;