diff --git "a/10 \347\253\240\347\254\221\345\256\271/20230306 \345\255\220\346\237\245\350\257\242.md" "b/10 \347\253\240\347\254\221\345\256\271/20230306 \345\255\220\346\237\245\350\257\242.md"
new file mode 100644
index 0000000000000000000000000000000000000000..170665d323e6a731f5e77c63594a3cc3451d06fb
--- /dev/null
+++ "b/10 \347\253\240\347\254\221\345\256\271/20230306 \345\255\220\346\237\245\350\257\242.md"	
@@ -0,0 +1,123 @@
+# 1、笔记
+
+```sql
+-- 什么子查询
+-- 嵌套在其它SQL语句中的select语句
+-- 子查询通常在外层语句之前优先执行，所以要用（）包括起来
+-- 子查询的结果，一般作为外层语句的条件，数据源等
+-- 形式一,select后面嵌套子查询
+select (子查询) from 表名 [where/having 条件];
+-- 形式二，在where/having 后面做条件
+select 字段名 from 表名 where/having (子查询);
+
+-- 当子查询放在where  、 having 后面当条件用时：
+-- 	单列单个值，可以直接用>,<,<=...!=，这些比较运算符
+-- 	单列多个值，要用in,not in 这种集合的比较
+-- 	单列多个值，可以用>,<,<=...!=，比较运算符，搭配any,all 这些关键字，一起使用
+
+
+
+-- 形式三，在from后面,形成一个临时表，必须加一个别名
+select 字段名 from (子查询) [as] 别名 [where/having 条件];
+
+
+-- 子查询的结果：
+-- 	单列单个值：可以放在select 后，也可以放where/having之后
+-- 	单列多个值：where后，或having后 ，不用直接用<,=,>= 这种单纯的比较运算符。但可以用搭配any(任意一个),all(所有的)等关键字--- 一起使用。还可以用in,not in这种表达式
+-- 	多列时，只能当临时表来表用，放在from后面，而且必须，给他取个别名
+```
+
+
+
+# 2、作业
+
+```sql
+use mockq;
+create table stuinfo(
+	stuno varchar(10),
+	stuname varchar(5),
+	stusex enum('男','女'),
+	stuage varchar(5),
+	stuaddress varchar(10),
+	stuseat int
+);
+create table stuexam(
+	examno int,
+	stuno varchar(10),
+	whitenexam varchar(5),
+	labexam varchar(5)
+);
+create table stumarks(
+	examno int,
+	stuid varchar(10),
+	score varchar(5)
+);
+insert into stuinfo values
+	('s2501','张秋利','男','20','美国硅谷',1),
+	('s2502','李斯文','女','18','湖北武汉',2),
+	('s2503','马文才','男','18','湖南长沙',3),
+	('s2504','欧阳俊雄','女','21','湖北武汉',4),
+	('s2505','梅超风','男','20','湖北武汉',5),
+	('s2506','陈旋风','男','19','美国硅谷',6);
+insert into stuexam VALUES
+	(1,'s2501','50','70'),
+	(2,'s2502','60','65'),
+	(3,'s2503','86','70'),
+	(4,'s2504','40','80'),
+	(5,'s2505','70','85'),
+	(6,'s2506','85','90');
+insert into stumarks VALUES
+	(1,'s2501','88'),
+	(2,'s2501','92'),
+	(3,'s2501','53'),
+	(4,'s2502','60'),
+	(5,'s2502','99'),
+	(6,'s2503','82');
+-- 在如图的数据表上完成以下题目
+-- 
+-- 1.查询出年龄比班上平均年龄大的学生的信息
+select * from stuinfo where stuage > (select avg(stuage) from stuinfo);
+-- 2.查询出每个学生的学号，姓名，性别和选修课程的最高分（stuMarks）
+-- select a.stuno,a.stuname,a.stusex,max(b.score)
+-- from stuinfo as a left join stumarks as b on a.stuno = b.stuid group by a.stuno;
+select b.stuno,b.stuname,b.stusex,max(a.score) from stumarks as a right join stuinfo as b on a.stuid = b.stuno group by b.stuno;
+-- 3.查询出每个学生的学号，姓名，性别和考试平均分（stuExam）
+select a.stuno,a.stuname,a.stusex,(b.whitenexam + b.labexam)/2 as '考试平均分' from stuinfo as a left join stuexam as b on a.stuno = b.stuno group by a.stuno;
+-- 4.查询性别是男并且年龄大于等于20的学生的信息(用两种方法实现：普通查询和子查询)
+select * from stuinfo where stusex = '男' and stuage >= 20;
+select stuinfo.* from stuinfo right join 
+(select * from stuinfo where stuage >= 20) as age on stuinfo.stuno = age.stuno where age.stusex = '男';
+-- 5.查询出年龄比所有男生年龄都大的女生的信息
+
+select * from stuinfo where stuage > (select max(stuage) from stuinfo where stusex = '男') and stusex = '女';
+-- 6.查询出所有选修课程都及格的学生的信息   （stuMarks）
+-- select * from stumarks where score > 60 and 
+SELECT *
+from stuinfo as a inner join stumarks as b on a.stuno = b.stuid where score > 60 ;
+-- 7.查询出参加考试的学生的信息（用表连接，in二种方法做）（stuMarks）
+select * from stuinfo as a right join stumarks as b on a.stuno = b.stuid;
+select * from stuinfo where stuno in (select stuno from stuinfo as a right join stumarks as b on a.stuno = b.stuid);
+-- 8.查询出没有参加考试的学生的信息（用表连接，in二种方法做）（stuMarks）
+select * from stuinfo as a left join stumarks as b on a.stuno = b.stuid where b.stuid is null;
+select * from stuinfo where stuno not in (select stuno from stuinfo as a right join stumarks as b on a.stuno = b.stuid);
+-- 9.将有一门成绩成绩大于90分的学生的基本信息查询出来（stuMarks）
+select * from stumarks where score > 90;
+select * from stuinfo as a inner join (select * from stumarks where score > 90) as b on a.stuno = b.stuid;
+-- 10.查询出平均成绩在80分以上的学生的基本信息（stuMarks）
+select avg(score) from stumarks group by stuid having avg(score) > 80;
+select stuinfo.*
+from (select stuid,avg(score) from stumarks group by stuid having avg(score) > 80) as a inner join stuinfo on a.stuid = stuinfo.stuno;
+-- 11.查询出某同学所有考试成绩比“张秋利”同学所有分数都高的学生基本信息（stuMarks）
+select max(score) from stumarks where stuid = (select stuno from stuinfo where stuname = '张秋利');
+select a.*
+from stuinfo as a inner join stumarks as b on a.stuno = b.stuid where b.score > (select max(score) from stumarks where stuid = (select stuno from stuinfo where stuname = '张秋利'));
+-- 12.查询出某同学所有考试成绩只需要比“张秋利”同学某个分数高的学生基本信息（stuMarks）
+select min(score) from stumarks where stuid = (select stuno from stuinfo where stuname = '张秋利');
+select a.*
+from stuinfo as a inner join stumarks as b on a.stuno = b.stuid where b.score > (select min(score) from stumarks where stuid = (select stuno from stuinfo where stuname = '张秋利')) group by a.stuno;
+-- 13.查询班上比所有男生年龄都要大的女生的信息
+select * from stuinfo where stuage > (select max(stuage) from stuinfo where stusex = '男') and stusex = '女';
+-- 14.查询出只是比某个男生年龄大的女生的信息
+select * from stuinfo where stuage > (select min(stuage) from stuinfo where stusex = '男') and stusex = '女';
+```
+