Sql取出各科分数前三名的学生，Sql各科成绩前三的学生

Posted 2021-06-09 蕃薯耀

 

Sql取出各科分数前三名的学生，Sql各科成绩前三的学生

 

 

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©Copyright 蕃薯耀 2021-06-09

https://www.cnblogs.com/fanshuyao/

 

一、取出各科成绩前三的学生

#取出各科成绩前三的学生

CREATE TABLE stu_score(

    id INT PRIMARY KEY AUTO_INCREMENT,
    stu_id INT,
    stu_name VARCHAR(50),
    clazz VARCHAR(20),
    score DOUBLE,
    remark VARCHAR(50)
);


INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (1, \'小赵\', \'语文\', 80);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (1, \'小赵\', \'数学\', 85);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (1, \'小赵\', \'英语\', 90);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (1, \'小赵\', \'化学\', 90);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (2, \'小钱\', \'语文\', 88);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (2, \'小钱\', \'数学\', 88);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (2, \'小钱\', \'英语\', 98);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (2, \'小钱\', \'化学\', 92);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (3, \'小孙\', \'语文\', 70);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (3, \'小孙\', \'数学\', 78);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (3, \'小孙\', \'英语\', 96);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (3, \'小孙\', \'化学\', 95);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (4, \'小李\', \'语文\', 85);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (4, \'小李\', \'数学\', 98);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (4, \'小李\', \'英语\', 88);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (4, \'小李\', \'化学\', 98);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (5, \'小王\', \'语文\', 90);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (5, \'小王\', \'数学\', 80);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (5, \'小王\', \'英语\', 85);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (5, \'小王\', \'化学\', 78);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (6, \'小陈\', \'语文\', 87);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (6, \'小陈\', \'数学\', 97);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (6, \'小陈\', \'英语\', 84);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (6, \'小陈\', \'化学\', 80);

INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (7, \'小朱\', \'语文\', 80);
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (7, \'小朱\', \'数学\', 88);#和小钱88分一样，并列第三
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (7, \'小朱\', \'英语\', 98);#并列第一
INSERT INTO stu_score(stu_id,stu_name,clazz,score) VALUES (7, \'小朱\', \'化学\', 95);#并列批二


SELECT * FROM stu_score ss ORDER BY ss.`clazz`,ss.`score` DESC;


#取出各科成绩前三的学生
#1、取出一名学生A某个学科的成绩
#2、然后和所有的学生同一个学科的成绩比较
#3、当存在该学科的成绩比学生A的成绩大且总人数不大于3，或者该学科成绩没有大于学生A的，则表示学生A的成绩在前三
#4、然后根据学科、分数（降序）排序取出
SELECT * FROM stu_score ss1 
WHERE (
  SELECT COUNT(*) FROM stu_score ss2 
  WHERE ss2.`clazz`=ss1.`clazz` AND ss2.`score` > ss1.`score`
) < 3 
ORDER BY ss1.`clazz`,ss1.`score` DESC;

 

 

最后的查询结果：

    id  stu_id  stu_name  clazz       score  remark  
------  ------  --------  ------     ------  --------
    16       4  小李        化学          98  (NULL)  
    12       3  小孙        化学          95  (NULL)  
    28       7  小朱        化学          95  (NULL)  
    14       4  小李        数学          98  (NULL)  
    22       6  小陈        数学          97  (NULL)  
     6       2  小钱        数学          88  (NULL)  
    26       7  小朱        数学          88  (NULL)  
     7       2  小钱        英语          98  (NULL)  
    27       7  小朱        英语          98  (NULL)  
    11       3  小孙        英语          96  (NULL)  
    17       5  小王        语文          90  (NULL)  
     5       2  小钱        语文          88  (NULL)  
    21       6  小陈        语文          87  (NULL)  

 截图：

 

 

二、取出各科成绩都不小于85分的学生

#取出各科成绩都不小于85分的学生
#如果一个学生所有学科的分数中，最小的都>=85，则表示该学生每科成绩都不小于85
SELECT stu_name FROM stu_score  GROUP BY stu_name HAVING MIN(score) >=85;

 

查询结果：

stu_name  
----------
小李    
小钱  

 

 

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©Copyright 蕃薯耀 2021-06-09

https://www.cnblogs.com/fanshuyao/