(1)mysql--查询成绩最高和最低的人

简单描述：
成绩表中有学生姓名、学生科目以及学生分数。查询分数最高和分数最低的学生的以及学生的分数。注意的点如下：

1、group by，select 选择的列，必须是group by 中的列，或者是函数形式。
2、利用MAX（） 和MIN（）sql函数。
3、建立的表结构如下。

-- ---------------------------- -- Table structure for grade -- ---------------------------- DROP TABLE IF EXISTS `grade`; CREATE TABLE `grade` (`stu_name` varchar(255) NOT NULL,`stu_subject` varchar(255) NOT NULL,`score` int(255) DEFAULT NULL,PRIMARY KEY (`stu_subject`,`stu_name`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;-- ---------------------------- -- Records of grade -- ---------------------------- INSERT INTO `grade` VALUES ('lilei', 'shuxue', '99'); INSERT INTO `grade` VALUES ('xiaoyong', 'shuxue', '66'); INSERT INTO `grade` VALUES ('lilei', 'yingyu', '80'); INSERT INTO `grade` VALUES ('xiaoyong', 'yingyu', '55'); INSERT INTO `grade` VALUES ('lilei', 'yuwen', '78'); INSERT INTO `grade` VALUES ('xiaoyong', 'yuwen', '88');

思路
1)按照科目分组查询成绩最高的人
SELECT grade.stu_subject, MAX(grade.score) as score from grade GROUP BY stu_subject;
2)显示出成绩最高的人的姓名和科目名称
SELECT grade.* from grade,
(SELECT grade.stu_subject, MAX(grade.score) as score from grade GROUP BY stu_subject )b
WHERE grade.score = b.score and grade.stu_subject = b.stu_subject;
3)显示出列标题.
SELECT “成绩最高”,grade.* from grade,
(SELECT grade.stu_subject, MAX(grade.score) as score from grade GROUP BY stu_subject )b
WHERE grade.score = b.score and grade.stu_subject = b.stu_subject;

成绩最低的也是如此就是利用MIN()函数, 如果需要同时查出, 可以用union 如下sql

SELECT "成绩最高",grade.* from grade, (SELECT grade.stu_subject, MAX(grade.score) as score from grade GROUP BY stu_subject )b WHERE grade.score = b.score and grade.stu_subject = b.stu_subject UNION SELECT "成绩最低",grade.* from grade, (SELECT grade.stu_subject, MIN(grade.score) as score from grade GROUP BY stu_subject )b WHERE grade.score = b.score and grade.stu_subject = b.stu_subject;

查询结果如下图所示:

总结:
路漫漫其修远兮,吾将上下而求索。

总结

以上是生活随笔为你收集整理的(1)mysql--查询成绩最高和最低的人的全部内容，希望文章能够帮你解决所遇到的问题。

如果觉得生活随笔网站内容还不错，欢迎将生活随笔推荐给好友。