SQL database query exercises, after-school exercises

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There is a database, including four tables: student table (Student), curriculum table (Course), grade table (Score) and teacher information table (Teacher)

Table (1) Student (student table)

attribute name	type of data	Can it be empty	meaning
Sno	varchar(20)	no	Student number (master code)
It takes off	varchar(20)	no	student name
Ssex	varchar(20)	no	student gender
Sbirthday	datetime	Can	student's date of birth
Class	varchar(20)	Can	student's class

Table (2) Course

attribute name	type of data	Can it be empty	meaning
Cno	varchar(20)	no	Course number (master code)
Cname	varchar(20)	no	Course Title
Tno	varchar(20)	no	Faculty number (external code)

Table (3) Score (score table)

attribute name	type of data	Can it be empty	meaning
Sno	varchar(20)	no	Student number (master code)
Cno	varchar(20)	no	Course number (external code)
Degree	Decimal	Can	score

Table (4) Student (teacher table)

attribute name	type of data	Can it be empty	meaning
Tno	varchar(20)	no	Faculty number (master code)
Tname	varchar(20)	no	Faculty name
Czech	varchar(20)	no	Faculty gender
Tbirthday	datetime	Can	Faculty's date of birth
Prof	varchar(20)	Can	job title
Depart	varchar(20)	no	Faculty's department

1. Query the Sname, Ssex and Class columns of all records in the Student table

   select Sname,Ssex,Class 
   from Student;

2. Query all the units of the teacher, that is, the non-repeated Depart column

   select distinct Depart 
   from teacher;

3. Query all records of the Student table

   select * 
   from Student;

4. Query all records with scores between 60 and 80 in the Score table

   select * 
   from Score 
   where Degree>60 and Degree<80;

5. Query the records with scores of 85, 86 or 88 in the Score table

   select * 
   from score 
   where Degree=85 or Degree=86 or Degree=88;

6. Query the "95031" class or the student records whose gender is "female" in the Student table

   select * 
   from student 
   where Class=95031 or Ssex='女';

7. Query all records of the Student table in descending order of Class

   select * 
   from student 
   order by Class desc;

8. Query all records in the Score table in ascending order of Cno and descending order of Degree

   select * 
   from score 
   order by Cno asc ,Degree desc;

9. Query the number of students in class "95031"

   select count(Class) as NumberofStudent 
   from student 
   where Class='95031';

10. Query the student number and course number of the student with the highest score in the Score table. (subquery or sort)

   select Sno,Cno 
   from score 
   where Degree=(select max(Degree) from score);

11. Query the average grade of each course

   select Cno,avg(Degree) 
   from score 
   group by Cno;

12. Query the average score of courses that have at least 5 students in the Score table and start with 3

   select Cno,avg(Degree) 
   from score 
   where Cno like '3%'group by Cno having count(Cno)>5;

13. Query the Sno column whose score is greater than 70 and less than 90

   select Sno 
   from score 
   where degree between 70 and 90;

14. Query the Sname, Cno and Degree columns of all students

   select Sname,Cno,Degree 
   from student 
   join score on student.Sno=score.Sno;

15. Query the Sno, Cname and Degree columns of all students

   select Sno,Cname,Degree 
   from score 
   join course on course.Cno=score.Cno;

16. Query the Sname, Cname and Degree columns of all students

   select Sname,Cname,Degree 
   from student 
   join score on student.Sno=score.Sno 
   join course on score.Cno=course.Cno;

17. Query the average score of the students in class "95033"

   select avg(Degree) 
   from score 
   join student on student.Sno=score.Sno 
   group by Class having Class='95033';

18. Suppose a grade table is created using the following command:
create table grade(low int(3),upp int(3),rank char(1))
insert into grade values(90,100,'A')
insert into grade values( 80,89,'B')
insert into grade values(70,79,'C')
insert into grade values(60,69,'D')
insert into grade values(0,59,'E')
now query all Classmate's Sno, Cno and rank columns

   select Sno,Cno,`rank` 
   from grade 
   join score on score.Degree between grade.low and grade.upp;

19. Query the records of all the students who have taken the "3-105" course and their grades are higher than those of the "109" students

   select * 
   from student,score 
   where  score.Cno='3-105'and student.Sno=Score.Sno 
   and score.Degree>(select Degree from score where Sno='109' 
   and score.Cno='3-105');

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20. Query the records of the scores of the students who have chosen to take multiple courses in the score, which are not the highest score
21. Query all records whose grades are higher than those whose student number is "109" and course number is "3-105"
22. Query the Sno, Sname and Birthday columns of all students born in the same year as the student number 108
23. Query the grades of students taught by teacher "Zhang Xu"
24. Query the name of the teacher who has more than 5 students taking a course
25. Query the records of all students in class 95033 and class 95031
26. Query the Cno of courses with a score of 85 or more
27. Check out the grades of the courses taught by the teachers of the "Computer Department"
28. Query the Tname and Prof of teachers with different professional titles in "Department of Computer Science" and "Department of Electronic Engineering"
29. Query the Cno, Sno, and Degree of the students whose elective number is "3-105" and whose grades are at least higher than the elective number "3-245", and sort by Degree from high to low
1. Query the Cno, Sno and Degree of the students whose elective number is "3-105" and whose grades are higher than the elective number "3-245".
31. Query the name, sex and birthday of all teachers and classmates
32. Query the name, sex and birthday of all "female" teachers and "female" classmates
33. Query the transcripts of students whose grades are lower than the average grade of the course
34. Query the Tname and Depart of all teachers
35. Query the Tname and Depart of all teachers who have not lectured
36. Query the class number with at least 2 boys
37. Query the records of students whose surname is not "Wang" in the Student table
38. Query the name and age of each student in the Student table
39. Query the maximum and minimum Sbirthday date values in the Student table
40. Query all records in the Student table in descending order of class number and age
41. Query "male" teachers and their courses
42. Query the Sno, Cno and Degree columns of the students with the highest scores
43. Query the Sname of all students with the same gender as "Li Jun"
44. Query the classmate Sname of the same gender and class as "Li Jun"
45. Query the transcripts of all "male" students who have taken the "Introduction to Computer" course

SQL database query exercises, after-school exercises

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