Week1: Database

bai2.sql

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+-- Bạn hãy viết một script để tạo các bản cho hệ thống với cấu trúc ở dưới
+USE ep_week1;
+
+create table if not exists Professor(
+	prof_id    int primary key auto_increment,
+    prof_lname varchar(50),
+    prof_fname varchar(50)
+);
+
+ create table if not exists Student(
+	stud_id 	int primary key auto_increment,
+    stud_lname	varchar(50),
+    stud_fname	varchar(50),
+    stud_street varchar(255),
+    stud_city	varchar(50),
+    stud_zip	varchar(10)
+ );
+
+ create table if not exists Room
+(
+    room_id  int primary key auto_increment,
+    room_loc varchar(50),
+    room_cap varchar(50),
+    class_id int
+);
+
+create table if not exists Course
+(
+    course_id   int primary key auto_increment,
+    course_name varchar(255)
+);
+
+create table if not exists Class
+(
+    class_id   int primary key auto_increment,
+    class_name varchar(255),
+    prof_id    int,
+    course_id  int,
+    room_id    int,
+    FOREIGN KEY (prof_id) REFERENCES Professor (prof_id),
+    FOREIGN KEY (course_id) REFERENCES Course (course_id),
+    FOREIGN KEY (room_id) REFERENCES Room (room_id)
+);
+
+alter table Room
+    add FOREIGN KEY (class_id) REFERENCES Class (class_id);
+
+create table if not exists Enroll
+(
+    stud_id  int,
+    class_id int,
+    grade    varchar(3),
+    primary key (stud_id, class_id),
+    FOREIGN KEY (stud_id) REFERENCES Student (stud_id),
+    FOREIGN KEY (class_id) REFERENCES Class (class_id)
+);
+
+
+

bai3.sql

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+use ep_week1;
+
+-- những cặp student-professor có dạy học nhau và số lớp mà họ có liên quan
+SELECT Student.stud_fname"Studen_Name", Professor.prof_fname as "Professor_Name", Class.class_id as "Class"
+FROM Student 
+INNER JOIN Enroll ON Student.stud_id = Enroll.stud_id
+INNER JOIN Class ON Class.class_id = Enroll.class_id
+INNER JOIN Professor ON Professor.prof_id = Class.prof_id;
+
+-- những course (distinct) mà 1 professor cụ thể đang dạy
+
+SELECT DISTINCT CONCAT(Professor.prof_lname, Professor.prof_fname),Course.course_name
+From Course
+INNER JOIN Class ON Course.course_id = Class.course_id
+INNER JOIN Professor ON Class.prof_id = Professor.prof_id;
+
+-- những course (distinct) mà 1 student cụ thể đang học
+select distinct concat(Student.stud_fname, " ", Student.stud_lname), Course.course_name
+from Student
+inner join Enroll on Enroll.stud_id = Student.stud_id
+inner join Class on Enroll.class_id = Class.class_id
+inner join Course on Course.course_id = Class.course_id;
+
+-- điểm số là A, B, C, D, E, F tương đương với 10, 8, 6, 4, 2, 0
+select * from Enroll;
+create view Student_Grade as
+select Enroll.stud_id, Enroll.class_id,
+case Enroll.grade 
+	when "A" then 10
+    when "B" then 8
+    when "C" then 6
+    when "D" then 4
+    when "E" then 2
+    when "F" then 0
+end as "gpa"
+from Enroll;
+
+ select * from Student_Grade;
+
+ -- điểm số trung bình của 1 học sinh cụ thể (quy ra lại theo chữ cái, và xếp loại học lực (weak nếu avg < 5, average nếu >=5 < 8, good nếu >=8 )
+ select Student.stud_id, 
+		Student.stud_fname,
+		AVG(Student_Grade.gpa) as 'average_score',
+case 
+	when AVG(Student_Grade.gpa) < 5 then 'week'
+    when AVG(Student_Grade.gpa) >= 8 then 'good'
+    else 'average'
+end as "assess"
+ from Student
+ inner join Student_Grade on Student_Grade.stud_id = Student.stud_id
+ group by Student.stud_id;
+
+ -- điểm số trung bình của các class (quy ra lại theo chữ cái)
+ select Class.class_id, Class.class_name, AVG(Student_Grade.gpa) as 'average_score',
+ case
+	when AVG(Student_Grade.gpa) < 5 then 'week'
+    when AVG(Student_Grade.gpa) >= 8 then 'good'
+    else 'average'
+ end as 'assess'
+ from Class
+ inner join Student_Grade on Student_Grade.class_id = Class.class_id
+ group by Class.class_id;
+
+ -- điểm số trung bình của các course (quy ra lại theo chữ cái)
+ select Course.course_id, Course.course_name, AVG(Student_Grade.gpa) as 'average_score',
+  case
+	when AVG(Student_Grade.gpa) < 5 then 'week'
+    when AVG(Student_Grade.gpa) >= 8 then 'good'
+    else 'average'
+ end as 'assess'
+ from Course 
+ inner join Class on Class.course_id = Course.course_id
+ inner join Student_Grade on Student_Grade.class_id = Class.class_id
+ group by Course.course_id