diff --git "a/7 \345\273\226\346\262\273\345\205\210/\344\275\234\344\270\232/2022-9-21\344\275\234\344\270\232.sql" "b/7 \345\273\226\346\262\273\345\205\210/\344\275\234\344\270\232/2022-9-21\344\275\234\344\270\232.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..ab5e3c67c39ab9e9155e92b716d8d3e486479c2f
--- /dev/null
+++ "b/7 \345\273\226\346\262\273\345\205\210/\344\275\234\344\270\232/2022-9-21\344\275\234\344\270\232.sql"	
@@ -0,0 +1,57 @@
+--13. 按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
+		--1.
+		select sc.sid,max(case when cid=01 then score end)'01',
+			   max(case when cid=02 then score end)'02',
+			   max(case when cid=03 then score end)'03',
+			   avg(score)平均成绩
+		from sc
+		group by sid
+		order by AVG(score) desc
+		;
+		--2.
+		select  sid,(select sid from sc sc1 where sc1.CId=01  and sc1.sid=sc.sid )'01',
+		(select score from sc sc1 where sc1.CId=02  and sc1.sid=sc.sid  )'02',
+		(select score from sc sc1 where sc1.CId=03  and sc1.sid=sc.sid  )'03',
+		avg(score)平均成绩
+		from sc
+		group by sid
+		order by AVG(score) desc;
+--14. 查询各科成绩最高分、最低分和平均分：
+
+--以如下形式显示：课程 ID，课程 name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率
+
+--及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90
+
+--要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列
+	select cid,count(*)选修人数,max(score)最高分,min(score)最低分,avg(score)平均分,
+		   (select cname from Course c where c.CId=sc.CId)学科,
+		   concat(count((case when score>=60 then '及格' end))*100/count(*),'%')及格,
+		   concat(count((case when score>=70 and score<80 then '中等' end))*100/count(*),'%')中等,
+		   concat(count((case when score>=80 and score<90 then '优良' end))*100/count(*),'%')优良,
+		   concat(count((case when score>=90 then '优秀' end))*100/count(*),'%')优秀
+	from sc
+	group by cid
+	order by count(*),cid
+	;
+--15. 按各科成绩进行排序，并显示排名， Score 重复时保留名次空缺
+		select *,RANK() over(partition by cid order by score desc) from sc;
+--15.1 按各科成绩进行排序，并显示排名， Score 重复时合并名次
+		select *,DENSE_RANK() over(partition by cid order by score desc) from sc;
+--16. 查询学生的总成绩，并进行排名，总分重复时保留名次空缺
+		select sid,sum(score),RANK() over(order by sum(score)desc) from sc
+		group by sid 
+		;
+--16.1 查询学生的总成绩，并进行排名，总分重复时不保留名次空缺
+		select sid,sum(score),DENSE_RANK() over(order by sum(score)desc) from sc
+		group by sid 
+		;
+--17. 统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[85-70]，[70-60]，[60-0] 及所占百分比
+		select cid,
+		   (select cname from Course c where c.CId=sc.CId)学科,
+		   concat(count((case when score>=60 then '及格' end))*100/count(*),'%')[100-85],
+		   concat(count((case when score>=70 and score<80 then '中等' end))*100/count(*),'%')[85-70],
+		   concat(count((case when score>=80 and score<90 then '优良' end))*100/count(*),'%')[70-60],
+		   concat(count((case when score>=90 then '优秀' end))*100/count(*),'%')[60-0]
+		from sc
+		group by sc.cid
+		order by count(*),sc.cid;
\ No newline at end of file
diff --git "a/7 \345\273\226\346\262\273\345\205\210/\347\254\224\350\256\260/2022-9-21\347\254\224\350\256\260.md" "b/7 \345\273\226\346\262\273\345\205\210/\347\254\224\350\256\260/2022-9-21\347\254\224\350\256\260.md"
new file mode 100644
index 0000000000000000000000000000000000000000..6be4ef13e0ba5306d0c7af922ccf79dae3fcdc7a
--- /dev/null
+++ "b/7 \345\273\226\346\262\273\345\205\210/\347\254\224\350\256\260/2022-9-21\347\254\224\350\256\260.md"	
@@ -0,0 +1,26 @@
+select * from tb_student
+
+--鏌ヨ骞撮緞鏈�澶х殑瀛︾敓淇℃伅锛岃姹傛樉绀猴細濮撳悕锛屾�у埆锛屽勾榫�
+select birth,name 濮撳悕,gender 鎬у埆 from tb_student 
+where birth = (select min(birth) from tb_student)
+
+--鎺掑簭鍑芥暟
+select birth,濮撳悕,鎬у埆  from (
+select birth,name 濮撳悕,gender 鎬у埆,row_number() over (order by birth ) as birth_rank from tb_student
+) as T1
+where T1.birth_rank = 1
+
+--鏌ヨ鐢风敓鍜屽コ鐢熶腑骞撮緞鏈�澶х殑瀛︾敓淇℃伅锛岃姹傛樉绀猴細濮撳悕锛屾�у埆锛屽勾榫�
+--闈炲叧鑱斿瓙鏌ヨ
+select birth,name 濮撳悕,gender 鎬у埆 from tb_student 
+where birth in (select min(birth) from tb_student group by gender)
+
+--鍏宠仈瀛愭煡璇細鍐呴儴鏌ヨ闇�瑕佸紩鐢ㄥ閮ㄨ〃宸叉煡璇㈠嚭鐨勪俊鎭�
+select birth,name 濮撳悕,gender 鎬у埆 from tb_student t1
+where birth = (select min(birth) from tb_student t2 where t2.gender=t1.gender)
+
+--绐楀彛鍑芥暟锛氭帓搴�
+select birth,濮撳悕,鎬у埆  from (
+select birth,name 濮撳悕,gender 鎬у埆,row_number() over (partition by gender order by birth ) as birth_rank from tb_student
+) as T1
+where T1.birth_rank = 1