求出小于45岁的各个老师所带的大于12岁的学生人数
实验数据:
drop table if exists tea_stu;
drop table if exists teacher;
drop table if exists student;
create table teacher(
teaID int primary key,
name varchar(50),
age int
);
create table student(
stuID int primary key,
name varchar(50),
age int
);
create table tea_stu(
teaID int references teacher(teaID),
stuID int references student(stuID)
);
insert into teacher values (1,'zxx',45), (2,'lhm',25) , (3,'wzg',26) , (4,'tg',27);
insert into student values (1,'wy',11), (2,'dh',25) , (3,'ysq',26) , (4,'mxc',27);
insert into tea_stu values (1,1), (1,2), (1,3);
insert into tea_stu values (2,2), (2,3), (2,4);
insert into tea_stu values (3,3), (3,4), (3,1);
insert into tea_stu values (4,4), (4,1), (4,2), (4,3);
发表评论