From f2e48b8610dad05ada8d5007afa9a145eee45972 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=AB=A0=E7=AC=91=E5=AE=B9?= <mockqqiu@gmail.com>
Date: Sun, 22 Oct 2023 23:59:12 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E6=B9=AB=E5=AE=9D=E7=9A=84=E6=97=A5?=
 =?UTF-8?q?=E5=BF=97?=
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---
 ...\347\273\217\345\205\27050\351\242\230.md" | 418 ++++++++++++++++++
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 create mode 100644 "10 \347\253\240\347\254\221\345\256\271/Day1020 mysql\347\273\217\345\205\27050\351\242\230.md"

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+++ "b/10 \347\253\240\347\254\221\345\256\271/Day1020 mysql\347\273\217\345\205\27050\351\242\230.md"	
@@ -0,0 +1,418 @@
+# 今日份日志
+
+初步接触mysql经典50题，复习以往的知识点
+
+
+
+# 练习
+
+```mysql
+
+# 学生表
+CREATE TABLE IF NOT EXISTS `student`(
+    `student_id` INT(10) NOT NULL AUTO_INCREMENT COMMENT '学号',
+    `student_name` VARCHAR(10) NOT NULL DEFAULT '匿名' COMMENT '姓名',
+    `birthday` DATETIME NOT NULL COMMENT '出生日期',
+    `gender` VARCHAR(10) NOT NULL DEFAULT '男' COMMENT '性别',
+    PRIMARY KEY(`student_id`)
+);
+
+INSERT INTO `student` VALUES
+(1 , '赵雷' , '1990-01-01' , '男'),
+(2 , '钱电' , '1990-12-21' , '男'),
+(3 , '孙风' , '1990-12-20' , '男'),
+(4 , '李云' , '1990-12-06' , '男'),
+(5 , '周梅' , '1991-12-01' , '女'),
+(6 , '吴兰' , '1992-01-01' , '女'),
+(7 , '郑竹' , '1989-01-01' , '女'),
+(8 , '张三' , '2017-12-20' , '女'),
+(9 , '李四' , '2017-12-25' , '女'),
+(10 , '李四' , '2012-06-06' , '女'),
+(11 , '赵六' , '2013-06-13' , '女'),
+(12 , '孙七' , '2014-06-01' , '女');
+-- 课程表
+CREATE TABLE IF NOT EXISTS `course`(
+    `course_id` INT(4) NOT NULL AUTO_INCREMENT COMMENT '课程编号',
+    `course_name` VARCHAR(10) NOT NULL COMMENT '课程名',
+    `teacher_id` INT(10) NOT NULL COMMENT '任课教师工号',
+    PRIMARY KEY(`course_id`)
+);
+
+INSERT INTO `course` VALUES
+(1, '语文', 2),
+(2, '数学', 1),
+(3, '英语', 3);
+# 教师表
+CREATE TABLE IF NOT EXISTS `teacher`(
+    `teacher_id` INT(10) NOT NULL AUTO_INCREMENT COMMENT '教师工号',
+    `teacher_name` VARCHAR(10) NOT NULL DEFAULT '匿名' COMMENT '教师姓名',
+    PRIMARY KEY(`teacher_id`)
+);
+
+INSERT INTO `teacher` VALUES
+(1, '高斯'),
+(2, '李白'),
+(3, 'Trump');
+
+-- 成绩表
+CREATE TABLE IF NOT EXISTS `score`(
+    `student_id` INT(10) NOT NULL COMMENT '学号',
+    `course_id` INT(4) NOT NULL COMMENT '课程编号',
+    `score` DECIMAL(18,1) COMMENT '成绩',
+    KEY(`course_id`)
+);
+
+INSERT INTO `score` VALUES
+(1 , 1 , 80),
+(1 , 2 , 90),
+(1 , 3 , 99),
+(2 , 1 , 70),
+(2 , 2 , 60),
+(2 , 3 , 80),
+(3 , 1 , 80),
+(3 , 2 , 80),
+(3 , 3 , 80),
+(4 , 1 , 50),
+(4 , 2 , 30),
+(4 , 3 , 20),
+(5 , 1 , 76),
+(5 , 2 , 87),
+(6 , 1 , 31),
+(6 , 3 , 34),
+(7 , 2 , 89),
+(7 , 3 , 98);
+
+
+
+
+#
+# ```
+#
+# ## 题目：
+# #
+# # 1. 查询" 1 "课程比" 2 "课程成绩高的学生的信息（学号、姓名、性别、出生日期）及课程分数
+select * from student join score s on student.student_id = s.student_id
+                      join course c on s.course_id = c.course_id;
+with
+    sc_1 as (select * from score where course_id = 1),
+    sc_2 as (select * from score where course_id = 2)
+select s.*,sc_1.score from sc_1,sc_2,student s
+           where sc_1.student_id = sc_2.student_id
+             and s.student_id = sc_1.student_id
+             and sc_1.score>sc_2.score;
+
+# # 2. 查询同时参与" 1 "课程和" 2 "课程考试的学生信息
+# select * from score where course_id between 1 and 2;
+with
+    co_1 as (select * from score where course_id = 1),
+    co_2 as (select * from score where course_id = 2)
+select student.* from student,co_1,co_2
+         where student.student_id = co_1.student_id
+         and co_1.student_id=co_2.student_id;
+
+# # 3. 查询存在" 1 "课程但可能不存在" 2 "课程的情况(不存在时显示为 null )
+with
+    co_1 as (select * from score where course_id = 1),
+    co_2 as (select * from score where course_id = 2)
+select student.* from student right join co_1 on student.student_id = co_1.student_id
+                                left join co_2 on co_1.student_id=co_2.student_id;
+
+# # 4. 查询不存在" 1 "课程但存在" 2 "课程的情况
+select * from student where student_id in (
+select student_id from score where score.student_id not in (select student_id from score where course_id = 1));
+
+# # 5. 查询平均成绩大于等于 60 分的同学的学生编号、姓名和平均成绩
+select
+    student.student_id,
+    student.student_name,
+    avg(score)
+from
+    score,student
+where
+    score.student_id = student.student_id
+group by
+    student_id
+having
+    avg(score) >= 60;
+# # 6. 查询在成绩表存在成绩的学生信息
+select * from student where student_id in (
+select distinct student_id from score where score is not null);
+
+# # 7. 查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩(没成绩的显示为 null )
+select
+    distinct s.student_id ,
+             s.student_name,
+             count(course_id) over (partition by score.student_id) 选课总数,
+             sum(score) over (partition by score.student_id) 总成绩
+from
+    score join student s on score.student_id = s.student_id;
+
+# # 8. 查询「李」姓老师的数量
+select count(teacher_id) from teacher where teacher_name like '李% ';
+# # 9. 查询学过「李白」老师授课的同学的信息
+select
+    s2.*
+from
+    teacher join course c on teacher.teacher_id = c.teacher_id
+        join score s on c.course_id = s.course_id
+        join student s2 on s.student_id = s2.student_id
+where teacher_name = '李白';
+
+# # 10. 查询没有学全所有课程的同学的信息
+select * from student where student_id in (
+select student_id from score group by student_id having count(*) < 3);
+
+# # 11. 查询至少有一门课与学号为" 1 "的同学所学相同的同学的信息
+select * from student where student_id in (
+select distinct student_id from score where course_id in (
+select course_id from score where student_id = 1) and student_id != 1);
+
+# # 12. 查询和" 1 "号的同学学习的课程完全相同的其他同学的信息
+with
+    a as (
+        select * from student where student_id in (
+        select student_id from score where course_id = (
+        select course_id from score where student_id = 1 limit 0,1))),
+    b as(
+        select * from student where student_id in (
+        select student_id from score where course_id = (
+        select course_id from score where student_id = 1 limit 1,1))),
+    c as(
+        select * from student where student_id in (
+        select student_id from score where course_id = (
+        select course_id from score where student_id = 1 limit 2,1)))
+select a.*
+from a join b on a.student_id = b.student_id
+    join c on c.student_id = a.student_id
+where a.student_id != 1;
+
+
+# # 13. 查询没学过「李白」老师讲授的任一门课程的学生姓名
+select student_name from student where student_id not in (
+select student_id from score where course_id = (
+select course_id from course where teacher_id = (
+select teacher_id from teacher where teacher_name = '李白')));
+
+# # 14. 查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩
+with
+    a as (select student_id from score where score < 60 group by student_id having count(student_id) >= 2)
+select
+    s.student_id,
+    student_name,
+    avg(score) 平均分
+from a join score on a.student_id = score.student_id
+        join student s on a.student_id = s.student_id
+group by s.student_id;
+# # 15. 检索" 1 "课程分数小于 60，按分数降序排列的学生信息
+select * from student where student_id in (
+select student_id from score where course_id = 1 and score < 60 order by score desc );
+
+# # 16. 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 *,avg(score) over (partition by student_id order by score desc ) 平均成绩 from score;
+
+# # 17. 查询各科成绩最高分、最低分和平均分
+select course_id, max(score),min(score),avg(score) from score group by course_id;
+
+# # 18. 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
+    c.course_id 课程ID ,
+    c.course_name 课程name,
+    max(score) 最高分,
+    min(score) 最低分,
+    round(avg(score),2) 平均分,
+    concat(round(sum(case when score >= 60 then 1 else 0 end)/count(*)*100,2),'%') 及格率,
+    concat(round(sum(case when score between 70 and 80 then 1 else 0 end)/count(*)*100,2),'%') 中等率,
+    concat(round(sum(case when score between 80 and 90 then 1 else 0 end)/count(*)*100,2),'%') 优良率,
+    concat(round(sum(case when score >= 90 then 1 else 0 end)/count(*)*100,2),'%') 优秀率
+from score s join course c on s.course_id = c.course_id
+group by c.course_id;
+
+
+# # 19. 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 course_id order by score desc ) 排名 from score;
+
+# # 20. 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 course_id order by score desc ) 排名 from score;
+
+# # 21. 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 distinct student_id,sum(score) over (partition by student_id ) 总成绩 from score order by 总成绩 desc ;
+
+# # 22. 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 distinct student_id,sum(score) over (partition by student_id ) 总成绩 from score order by 总成绩 desc ;
+
+
+# # 23. 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
+    course_id,
+    (select course_name from course where score.course_id = course_id) 课程名称,
+    sum(case when score <=100 and score >= 85 then 1 else 0 end ) `[100-85]`,
+    sum(case when score <85 and score >= 70 then 1 else 0 end ) `[85-70]`,
+    sum(case when score <70 and score >= 60 then 1 else 0 end ) `[70-60]`,
+    sum(case when score <60 and score >=0 then 1 else 0 end ) `[60-0]`,
+
+    sum(case when score <=100 and score >= 85 then 1 else 0 end )/count(*),
+    sum(case when score <85 and score >= 70 then 1 else 0 end )/count(*),
+    sum(case when score <70 and score >= 60 then 1 else 0 end )/count(*),
+    sum(case when score <60 and score >=0 then 1 else 0 end ) /count(*)
+from
+    score
+group by course_id;
+
+
+
+
+
+
+
+
+
+# # 24. 查询各科成绩前三名的记录
+select
+    c.course_id,course_name,s.student_id,student_name,score
+from
+    (select *
+     from score s1
+     where (select count(*)
+            from score s2
+            where s1.course_id = s2.course_id and s1.score < s2.score) < 3) t1
+join student s on s.student_id = t1.student_id
+join course c on c.course_id = t1.course_id
+order by c.course_id,score desc ;
+# # 25. 查询每门课程被选修的学生数
+select
+    *
+from
+    course c join
+        (select course_id,count(*)
+         from score group by course_id) t1 on c.course_id = t1.course_id;
+# # 26. 查询出只选修两门课程的学生学号和姓名
+select
+    student_id,student_name
+from student
+where student_id in (
+select
+    student_id
+from
+    score
+group by student_id having count(*) = 2);
+# # 27. 查询男生、女生人数
+select gender,count(*) from student group by gender;
+# # 28. 查询名字中含有「风」字的学生信息
+select * from student where student_name like '%风%';
+# # 29. 查询同名同性学生名单，并统计同名人数
+select
+    count(*)
+from student
+    group by student_name,gender
+    having count(*) > 1;
+
+# # 30. 查询 1990 年出生的学生名单
+select * from student where year(birthday) = 1990;
+
+# # 31. 查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列
+select course_id, avg(score) from score group by course_id order by avg(score) desc ,course_id;
+# # 32. 查询平均成绩大于等于 85 的所有学生的学号、姓名和平均成绩
+with
+    a as(
+select student_id,avg(score) avg_score from score group by student_id having avg(score) > 85)
+select s.student_id,student_name,avg_score from a join student s on a.student_id = s.student_id;
+# # 33. 查询课程名称为「数学」，且分数低于 60 的学生姓名和分数
+with
+    a as (
+select * from score where course_id = (
+select course_id from course where course_name = '数学') and score < 60)
+select * from student s join a on s.student_id = a.student_id;
+# # 34. 查询所有学生的课程及分数情况（存在学生没成绩，没选课的情况）
+select
+    s.student_id,student_name,
+    sum(case course_id when 1 then score else 0 end) 语文,
+    sum(case course_id when 2 then score else 0 end) 数学,
+    sum(case course_id when 3 then score else 0 end) 英语
+from student st join score s on st.student_id = s.student_id
+group by s.student_id;
+# # 35. 查询任何一门课程成绩在 70 分以上的姓名、课程名称和分数
+select
+    student_name,course_name,score
+from
+    score sc join student s on sc.student_id = s.student_id
+    join course c on sc.course_id = c.course_id
+where score > 70;
+# # 36. 查询不及格的课程
+select
+    student_id,course_name,score
+from
+    score s join course c on s.course_id = c.course_id
+where score < 60;
+# # 37. 查询课程编号为 1 且课程成绩在 80 分以上的学生的学号和姓名
+select
+    student_id,student_name
+from
+    student st
+where student_id in (
+    select student_id from score where course_id = 1 and score > 80
+    );
+
+# # 38. 求每门课程的学生人数
+select
+    c.course_id,course_name,cou_stu
+from
+    course c join (select course_id,count(*) cou_stu from score group by course_id) t1
+on c.course_id = t1.course_id;
+
+# # 39. 成绩不重复，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩
+select
+    s.*,score
+from
+    student s  join (select student_id,score from score sc join (select course_id from course c join teacher t on c.teacher_id = t.teacher_id where teacher_name = '张三')
+        t2 on sc.course_id = t2.course_id order by score desc limit 1) t1
+    on s.student_id = t1.student_id;
+
+
+# # 40. 成绩有重复的情况下，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩
+select
+    s.*,score
+from
+    student s  join (select student_id,score from score sc join (select course_id from course c join teacher t on c.teacher_id = t.teacher_id where teacher_name = '张三')
+        t2 on sc.course_id = t2.course_id order by score desc limit 1) t1
+    on s.student_id = t1.student_id;
+
+# # 41. 查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
+
+with
+    a as ( select * from score where course_id = 1 ),
+    b as ( select * from score where course_id = 2 ),
+    c as ( select * from score where course_id = 3 )
+select * from a join b on a.student_id = b.student_id
+                join c on a.student_id = c.student_id
+where a.score = b.score or a.score = c.score or b.score = c.score;
+# # 42. 查询每门功成绩最好的前两名、
+with
+    a as (select *,row_number() over (partition by course_id order by score desc) 排名 from score)
+select * from a where 排名 <= 2;
+
+# # 43. 统计每门课程的学生选修人数（超过 5 人的课程才统计）。
+select course_id, count(*) from score group by course_id having count(*)>5;
+# # 44. 检索至少选修两门课程的学生学号
+select student_id from score group by student_id having count(*) >=2;
+# # 45. 查询选修了全部课程的学生信息
+select * from student where student_id in (
+select student_id from score group by student_id having count(*) = 3);
+# # 46. 查询各学生的年龄，只按年份来算
+select student_name ,year(now())-year(birthday) from student;
+# # 47. 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一
+# select * from student;
+select student_name,timestampdiff(year,birthday,now()) from student;
+# # 48. 查询本周过生日的学生
+select * from student
+where week(birthday,1) = week(now(),1);
+# # 49. 查询下周过生日的学生
+select * from student
+where week(birthday,1) = week(now(),1)+1;
+# # 50. 查询本月过生日的学生
+select * from student where month(birthday) = month(now());
+# # 51. 查询下月过生日的学生
+select * from student where month(birthday) = month(now())+1;
+
+```
+
-- 
Gitee


From 527cf75fe35bf0b98539d5bdc46c9734e9547cc4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=AB=A0=E7=AC=91=E5=AE=B9?= <mockqqiu@gmail.com>
Date: Mon, 23 Oct 2023 23:54:31 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=B9=AB=E5=AE=9D=E7=9A=84=E6=97=A5?=
 =?UTF-8?q?=E5=BF=97?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ...y1023 mysql\345\210\235\345\244\215\344\271\240.md" | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 "10 \347\253\240\347\254\221\345\256\271/Day1023 mysql\345\210\235\345\244\215\344\271\240.md"

diff --git "a/10 \347\253\240\347\254\221\345\256\271/Day1023 mysql\345\210\235\345\244\215\344\271\240.md" "b/10 \347\253\240\347\254\221\345\256\271/Day1023 mysql\345\210\235\345\244\215\344\271\240.md"
new file mode 100644
index 0000000..a8e3092
--- /dev/null
+++ "b/10 \347\253\240\347\254\221\345\256\271/Day1023 mysql\345\210\235\345\244\215\344\271\240.md"	
@@ -0,0 +1,10 @@
+# 今日份日志
+
+今日份复习：
+
+1. er图
+2. CDM模型
+3. 范式（略过）
+4. 视图
+5. 常用函数
+6. 存储过程
\ No newline at end of file
-- 
Gitee