MySQl查询各科成绩前三名

创建表

create table student ( 
    name varchar(20) , 
    lesson varchar(20), 
    mark float 
) ;

 

插入数据

insert into student values(\'john\',\'Math\',60); 
insert into student values(\'john\',\'Eng\',50); 
insert into student values(\'john\',\'HIstory\',56); 

insert into student values(\'Mike\',\'Eng\',51); 
insert into student values(\'Mike\',\'Math\',59); 
insert into student values(\'Mike\',\'HIstory\',55); 

insert into student values(\'Mark\',\'Eng\',71); 
insert into student values(\'Mark\',\'Math\',89); 
insert into student values(\'Mark\',\'HIstory\',95); 

insert into student values(\'张三\',\'Eng\',61); 
insert into student values(\'张三\',\'Math\',79); 
insert into student values(\'张三\',\'HIstory\',85); 

insert into student values(\'李明\',\'Eng\',51); 
insert into student values(\'李明\',\'Math\',69); 
insert into student values(\'李明\',\'HIstory\',95);

查询

#方法一
SELECT T1.*
FROM student T1
LEFT JOIN (
SELECT DISTINCT lesson,mark
FROM student) T2 ON T1.lesson = T2.lesson AND T1.mark <= T2.mark GROUP BY name,lesson,mark 
HAVING COUNT(1) <= 3  ORDER BY lesson,mark DESC;


#方法二
SELECT s1.*
FROM student s1
WHERE (
SELECT COUNT(1)
FROM student s2
WHERE s1.lesson=s2.lesson AND s1.mark<s2.mark)<3
ORDER BY s1.lesson,s1.mark DESC;