diff --git "a/\346\210\264\344\277\212\351\224\213/\344\275\234\344\270\232/2022.9.21\344\275\234\344\270\232.sql" "b/\346\210\264\344\277\212\351\224\213/\344\275\234\344\270\232/2022.9.21\344\275\234\344\270\232.sql"
new file mode 100644
index 0000000000000000000000000000000000000000..15c6d9571279b3db521ec3e4d1cdf5ab8c563657
--- /dev/null
+++ "b/\346\210\264\344\277\212\351\224\213/\344\275\234\344\270\232/2022.9.21\344\275\234\344\270\232.sql"
@@ -0,0 +1,71 @@
+--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
+select sc.SId,c.Cname,score,t.平均分 from sc
+inner join Course c on c.cid = sc.CId
+inner join
+(
+select sid,avg(score)平均分 from sc
+group by sid 
+) t
+on t.SId = sc.sid 
+
+order by t.平均分 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 sc.CId,c.Cname,
+(select max(score) from sc sc1 where sc.CId = sc1.CId)最高分,
+(select min(score) from sc sc1 where sc.CId = sc1.CId)最低分,
+convert(decimal(5,2),(select avg(score) from sc sc1 where sc.cid = sc1.cid))平均分,
+concat(convert(decimal(5,2),(select (count(*)*100)/1.0/(select count(*) from sc sc3 where sc3.cid = sc.cid ) from sc sc2 where sc.cid = sc2.cid and sc2.score >= 60)),'%') 及格率,
+concat(convert(decimal(5,2),(select (count(*)*100)/1.0/(select count(*) from sc sc3 where sc3.cid = sc.cid ) from sc sc2 where sc.cid = sc2.cid and sc2.score  between 70 and 80)),'%') 中等率,
+concat(convert(decimal(5,2),(select (count(*)*100)/1.0/(select count(*) from sc sc3 where sc3.cid = sc.cid ) from sc sc2 where sc.cid = sc2.cid and sc2.score between 80 and 90)),'%') 优良率,
+concat(convert(decimal(5,2),(select (count(*)*100)/1.0/(select count(*) from sc sc3 where sc3.cid = sc.cid ) from sc sc2 where sc.cid = sc2.cid and sc2.score >= 90)),'%') 优秀率
+from sc
+inner join Course c 
+on c.CId = sc.CId
+group by sc.CId,c.Cname
+
+
+--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 s.sid,sname,t1.语文排名,t2.数学排名,t3.英语排名 from student s
+left join
+(
+select sid,rank() over(order by score desc) 语文排名 from sc where cid = '01'
+) t1 on t1.sid = s.sid 
+inner join
+(
+select sid,rank() over(order by score desc) 数学排名 from sc where cid = '02'
+) t2 on t2.sid = s.sid
+left join 
+(
+select sid,rank() over(order by score desc) 英语排名 from sc where cid = '03'
+) t3 on t3.sid = s.sid
+--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 s.sid,sname,t1.语文排名,t2.数学排名,t3.英语排名 from student s
+left join
+(
+select sid,dense_rank() over(order by score desc) 语文排名 from sc where cid = '01'
+) t1 on t1.sid = s.sid 
+inner join
+(
+select sid,dense_rank() over(order by score desc) 数学排名 from sc where cid = '02'
+) t2 on t2.sid = s.sid
+left join 
+(
+select sid,dense_rank() over(order by score desc) 英语排名 from sc where cid = '03'
+) t3 on t3.sid = s.sid
+--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 t.SId,t.总分,dense_rank() over (order by 总分 desc) 排名
+from
+(
+select sid,sum(score) 总分 from sc
+group by sid 
+) t
+--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 t.SId,t.总分,rank() over (order by 总分 desc) 排名
+from
+(
+select sid,sum(score) 总分 from sc
+group by sid 
+) t
\ No newline at end of file
diff --git "a/\346\210\264\344\277\212\351\224\213/\347\254\224\350\256\260/2022.9.21--\345\205\263\350\201\224 \345\255\220\346\237\245\350\257\242.md" "b/\346\210\264\344\277\212\351\224\213/\347\254\224\350\256\260/2022.9.21--\345\205\263\350\201\224 \345\255\220\346\237\245\350\257\242.md"
new file mode 100644
index 0000000000000000000000000000000000000000..c7d14426c53000ad9d1d86a70263a5ef766496f9
--- /dev/null
+++ "b/\346\210\264\344\277\212\351\224\213/\347\254\224\350\256\260/2022.9.21--\345\205\263\350\201\224 \345\255\220\346\237\245\350\257\242.md"	
@@ -0,0 +1,12 @@
+# 1.鍏宠仈瀛愭煡璇�
+
+**锛�1锛夊厛浠庝富鏌ヨ鐨勮〃涓殑鍒楀彇鍑虹涓�涓�硷紝杩涘叆瀛愭煡璇腑锛屽緱鍒板瓙鏌ヨ缁撴灉锛岀劧鍚庤繑鍥炵埗鏌ヨ锛屽垽鏂埗鏌ヨ鐨剋here瀛愬彞鏉′欢锛屽垯杩斿洖鏁翠釜璇彞鐨勭1鏉＄粨鏋溿��**
+
+**锛�2锛夐噸澶嶄笂杩版搷浣滐紝鐩村埌鎵�鏈変富鏌ヨ涓殑琛ㄤ腑鐨勫垪璁板綍鍙栧畬涓烘銆傚緱鍑烘暣涓鍙ョ殑缁撴灉闆嗭紝灏辨槸鏈�鍚庣殑绛旀銆�**
+
+```sql
+--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)
+```
+