建表

# 学生表
create table t_student
(stu_id   varchar(10),stu_name varchar(10),stu_age  datetime,stu_sex  varchar(10)
);# 课程表
create table t_t_course
(c_id    varchar(10),c_name  varchar(10),c_teaid varchar(10)
);# 教师表
create table t_t_teacher
(tea_id   varchar(10),tea_name varchar(10)
);# 成绩表
create table t_t_score
(s_stuid varchar(10),s_cid   varchar(10),s_score decimal(18, 1)
);-- 向t_student表插入数据
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('01', '赵雷', '1990-01-01', '男');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('02', '钱电', '1990-12-21', '男');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('03', '孙风', '1990-12-20', '男');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('04', '李云', '1990-12-06', '男');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('05', '周梅', '1991-12-01', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('06', '吴兰', '1992-01-01', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('07', '郑竹', '1989-01-01', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('09', '张三', '2017-12-20', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('10', '李四', '2017-12-25', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('11', '李四', '2012-06-06', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('12', '赵六', '2013-06-13', '女');
insert into t_student(stu_id, stu_name, stu_age, stu_sex)
values ('13', '孙七', '2014-06-01', '女');-- 向t_t_course表插入数据
insert into t_t_course(c_id, c_name, c_teaid)
values ('01', '语文', '02');
insert into t_course(c_id, c_name, c_teaid)
values ('02', '数学', '01');
insert into t_course(c_id, c_name, c_teaid)
values ('03', '英语', '03');-- 向t_t_teacher表插入数据
insert into t_teacher(tea_id, tea_name)
values ('01', '张三');
insert into t_teacher(tea_id, tea_name)
values ('02', '李四');
insert into t_teacher(tea_id, tea_name)
values ('03', '王五');-- 向t_t_score表插入数据
insert into t_score(s_stuid, s_cid, s_score)
values ('01', '01', 80);
insert into t_score(s_stuid, s_cid, s_score)
values ('01', '02', 90);
insert into t_score(s_stuid, s_cid, s_score)
values ('01', '03', 99);
insert into t_score(s_stuid, s_cid, s_score)
values ('02', '01', 70);
insert into t_score(s_stuid, s_cid, s_score)
values ('02', '02', 60);
insert into t_score(s_stuid, s_cid, s_score)
values ('02', '03', 80);
insert into t_score(s_stuid, s_cid, s_score)
values ('03', '01', 80);
insert into t_score(s_stuid, s_cid, s_score)
values ('03', '02', 80);
insert into t_score(s_stuid, s_cid, s_score)
values ('03', '03', 80);
insert into t_score(s_stuid, s_cid, s_score)
values ('04', '01', 50);
insert into t_score(s_stuid, s_cid, s_score)
values ('04', '02', 30);
insert into t_score(s_stuid, s_cid, s_score)
values ('04', '03', 20);
insert into t_score(s_stuid, s_cid, s_score)
values ('05', '01', 76);
insert into t_score(s_stuid, s_cid, s_score)
values ('05', '02', 87);
insert into t_score(s_stuid, s_cid, s_score)
values ('06', '01', 31);
insert into t_score(s_stuid, s_cid, s_score)
values ('06', '03', 34);
insert into t_score(s_stuid, s_cid, s_score)
values ('07', '02', 89);
insert into t_score(s_stuid, s_cid, s_score)
values ('07', '03', 98);

练习

# **33. 查询学生的总成绩，并按照总成绩依次进行排名**（不保留名次空缺）
select s.stu_id, s.stu_name, SUM(SC.s_score), rank() over ( order by SUM(SC.s_score) DESC )
from t_student sinner join t_score sc on s.stu_id = sc.s_stuid
GROUP BY s.stu_id, s.stu_name;# **34. 统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[85-70]，[70-60]，[60-0] 及所占百分比**
select (select Count(*) from t_score sc1 where sc1.s_score >= 85 and sc1.s_cid = co.c_id) AS '100-85',concat(FORMAT((select Count(*) from t_score sc1 where sc1.s_score >= 85 and sc1.s_cid = co.c_id) /(select Count(*) from t_score sc2 where sc2.s_cid = co.c_id) * 100, 2),'%')                                                                        AS '100-85%',(select Count(*)from t_score sc1where sc1.s_score >= 70and sc1.s_score < 85and sc1.s_cid = co.c_id)                                                        AS '85-70',concat(FORMAT((select Count(*)from t_score sc1where sc1.s_score >= 70and sc1.s_score < 85and sc1.s_cid = co.c_id) /(select Count(*) from t_score sc2 where sc2.s_cid = co.c_id) * 100, 2),'%')                                                                        AS '85-70%',(select Count(*)from t_score sc1where sc1.s_score >= 60and sc1.s_score < 70and sc1.s_cid = co.c_id)                                                        AS '70-60',concat(FORMAT((select Count(*)from t_score sc1where sc1.s_score >= 60and sc1.s_score < 70and sc1.s_cid = co.c_id) /(select Count(*) from t_score sc2 where sc2.s_cid = co.c_id) * 100, 2),'%')                                                                        AS '70-60%',(select Count(*)from t_score sc1where sc1.s_score < 60and sc1.s_cid = co.c_id)                                                        AS '60-0',concat(FORMAT((select Count(*) from t_score sc1 where sc1.s_score < 60 and sc1.s_cid = co.c_id) /(select Count(*) from t_score sc2 where sc2.s_cid = co.c_id) * 100, 2),'%')                                                                        AS '60-0%',co.c_id,co.c_name
from t_course coinner join t_score sc on sc.s_cid = co.c_idinner join t_student s on sc.s_stuid = s.stu_id
group by co.c_id, co.c_name;# 35. 查询各科成绩前三名的记录
#在where中不能直接使用窗口函数的别名需要使用子查询
SELECT *
FROM (SELECT sc.s_cid, s.*, RANK() OVER (PARTITION BY sc.s_cid ORDER BY sc.s_score) AS rFROM t_score scINNER JOIN t_student s ON sc.s_stuid = s.stu_id) ranked
WHERE r <= 3;# 36. 查询每个同学的学号、姓名、选课总数、总成绩
select s.stu_id, s.stu_name, count(*), sum(sc.s_score)
from t_student sinner join t_score sc on s.stu_id = sc.s_stuid
group by s.stu_id, s.stu_name;# **37. 查询编号是2的课程比编号是1的课程最高成绩高的学生姓名和成绩**
select s.stu_name, sc.s_score
from t_student sinner join t_score sc
on s.stu_id = sc.s_stuid
where sc.s_cid = 2and sc.s_score > (select max(sc1.s_score) from t_score sc1 where sc1.s_cid =1);