create table `course`(`id` int(11) not null auto_increment,`sid` int(11) not null comment '学号',`cid` int(11) not null comment '课程编号',`cname` char(50) not null comment '课程名称',`score` int(11) not null comment '分数',primary key(`id`))engine = innodb;
select distinct cid,cname from course where cid not in (select cid from course where score > 60 and sid=20190001)
select distinct cid,cname from course where cid in (select cid from course where score < 60) and sid=20190001
select distinct cid,cname from course where cid not in (select cid from course where score > 60) and sid=20190001
select distinct cid,cname from course where cid in (select cid from course where score < 60 and sid=20190001)
