创建三个表a、b、c

create table `a`(
	`id` int(10),
	`name` VARCHAR(20),
	`age` int(5),
	`sex` int(1)
);
CREATE table `b`
(
	`id` int(10),
	`bid` char(10),
	grade CHAR(20)
);
CREATE table `c`(
	`bid` char(10),
	`cname` char(20),
	`teacher` char(20)
)

表a中的数据

表b中的数据

表c中的数据

1.查询出学习成绩70分以上的学生姓名与成绩与学科；

SELECT name,grade,cname FROM a,b,c where a.id = b.id and c.bid = b.bid and grade>70

2.查询姓名以mi结尾的学生姓名及其任课老师姓名；

SELECT name,teacher FROM a,b,c where a.id = b.id and c.bid = b.bid and name like ‘%ng’

3.选修课名为math的学生学号与姓名;

SELECT a.id,name FROM a,b,c where a.id = b.id and c.bid = b.bid and cname = ‘math’

4.选修课号为C4的学生学号；

SELECT a.id FROM a,b,c where a.id = b.id and c.bid = b.bid and b.bid = ‘c4’

5.请问每科各有那些学生求姓名成绩；

SELECT a.name,grade,cname FROM a,b,c where a.id = b.id and c.bid = b.bid

6.请问总分在80分以上的学生姓名及学科；

SELECT a.name,cname FROM a,b,c where a.id = b.id and c.bid = b.bid and grade>80

7.请问考试不及格的考生姓名以及科目名称；

SELECT a.name,cname FROM a,b,c where a.id = b.id and c.bid = b.bid and grade<60

8.找出所有科目中最高分的学生姓名成绩

SELECT any_value(a.name),any_value(grade),max(cname) FROM a,b,c where a.id = b.id and c.bid = b.bid ORDER BY cname desc

9.各个科目的平均成绩各是多少；

SELECT avg(grade),cname FROM a,b,c where a.id = b.id and c.bid = b.bid GROUP BY cname

10.显示出参加考试的学生的学号和姓名；

SELECT a.id,name FROM a,b,c where a.id = b.id and c.bid = b.bid

11.请问 Ye Xiaoming一共参加了几门科目的考试；

SELECT a.id,cname FROM a,b,c where a.id = b.id and c.bid = b.bid and name=‘Ye Xiaoming’

12.请求出Ye Xiaoming同学所有任课老师的名字及其所教的课程名；

SELECT cname,teacher FROM a,b,c where a.id = b.id and c.bid = b.bid and name=‘Ye Xiaoming’

13.求每个同学的年龄和性别，姓名

SELECT name,age,sex FROM a,b,c where a.id = b.id and c.bid = b.bid

14.请问武老师教什么课程，以及他班上所有学生的姓名；

SELECT name,cname FROM a,b,c where a.id = b.id and c.bid = b.bid and teacher like ‘wu%’

15.统计art选修课中有多少男生和女生,(1表示男生，0表示女生)

SELECT COUNT(sex),sex FROM a,b,c where a.id = b.id and c.bid = b.bid and cname=‘art’ GROUP BY sex