1 create table t_class2(
2 name varchar2(255),
3 subject varchar2(255),
4 score integer,
5 stuid integer
6 )
7
8 insert into t_class2 values('张三','数学',89,1);
9 insert into t_class2 values('张三','语文',80,1);
10 insert into t_class2 values('张三','英语',70,1);
11
12
13 insert into t_class2 values('李四','数学',90,2);
14 insert into t_class2 values('李四','语文',70,2);
15 insert into t_class2 values('李四','英语',80,2);
16
17 select * from t_class2
18
19
20 --计算每个人的总成绩并排名 desc降序排列 sum()聚合函数求总
21 select name, sum(score) sumscore from t_class2 group by name order by sumscore desc
22
23
24 --计算每一个人的平均成绩 avg()聚合函数求平均值
25 select name, avg(score) avgscore from t_class2 group by name
26
27
28 --计算每个人的单科最高成绩 max()聚合函数求最大值
29 select name,max(score) maxscore from t_class2 group by name
30
31
32 --列出每一科成绩最好的学生
33
34 select c2.name, c2.subject,c2.score from t_class2 c2 ,
35 ( select subject, max(score) maxscore from t_class2 group by subject) c1
36 where c2.subject=c1.subject and c2.score=c1.maxscore
