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  • mysql实现分组查询每个班级的前三名

    1、创建表

    drop table student;
    create table student(
    	id varchar(20),-- 编号
    	class varchar(20),-- 年级
    	score int-- 分数
    );
    

    2、创建测试数据

    delete from student;
    insert student values('1','一年级',82);
    insert student values('2','一年级',95);
    insert student values('3','一年级',82);
    insert student values('4','一年级',40);
    insert student values('5','一年级',20);
    insert student values('6','二年级',95);
    insert student values('7','二年级',40);
    insert student values('8','二年级',3);
    insert student values('9','二年级',60);
    insert student values('10','二年级',10);
    insert student values('11','三年级',70);
    insert student values('12','三年级',60);
    insert student values('13','三年级',40);
    insert student values('14','三年级',90);
    insert student values('15','三年级',20);
    

    3、查询每个班级的前三名

    select a.class,a.score 
    from student a 
    where (select count(*) from student where class=a.class and a.score<score)<3
    order by a.class,a.score desc;
    
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  • 原文地址:https://www.cnblogs.com/caibaotimes/p/13714505.html
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