一、(having，group by，select嵌套放在select里)

可参考 https://www.jianshu.com/p/8b135d373df1

二、(not in，distinct去重，select嵌套放在where里)

表的内容如下：

实现功能：查询没学过"张三"老师授课的同学的信息

实现语句：

SELECT student.s_id,student.s_name FROM student WHERE s_id

not in (SELECT distinct( score.s_id) FROM score,course,teacher WHERE score.c_id=course.

c_id AND course.t_id=teacher.t_id AND teacher.t_name='张三');

三，(select嵌套放在from里)表可参照2

实现功能：查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息

实现语句：

SELECT *from (SELECT s_id,s_score from score WHERE score.c_id

="01")as t1,(SELECT s_id,s_score from score WHERE score.c_id="02")

as t2 WHERE t1.s_id=t2.s_id