Мне трудно подвести итоги таблицы SQL.
Objective: from the given tables I have to join and summarize the table.
col1 = Name_of_student,
col2 = Name_of_subject(where she/he scored highest),
col3= highest_number,
col4 = faculty_Name(where she/he scored highest),
col5 = Name_of_subject(where she/he scored lowest),
col6 = lowest marks,
col7 = faculty_Name(where she/he scored lowest)
Примечание - мне нужно написать только один запрос для данного вывода.
Там четыре таблицы:
- Студенты.
- Students_subject.
- Факультет.
- Marks.
Вы можете скопировать код в моем скрипте SQL для понимания таблиц.
create database university ;
use university ;
create table students (id int auto_increment primary key,
student_name varchar(250) NOT NULL,
dob DATE NOT NULL) ;
create table faculty ( id int auto_increment primary key,
faculty_name varchar(250) NOT NULL,
date_of_update datetime default NOW()) ;
create table Students_subject ( id int auto_increment primary key,
subject_name varchar(250) default 'unknown' NOT NULL,
subject_faculty int not null,
foreign key(subject_faculty) references faculty(id));
create table marks (id int auto_increment primary key,
student_id int NOT NULL,
subject_id int NOT NULL,
marks int NOT NULL,
date_of_update datetime default now() ON UPDATE NOW(),
foreign key(student_id) references students(id),
foreign key(subject_id) references students_subject(id));
insert into students ( student_name, dob) values
('rob', '2001-03-06'),
('bbb', '2001-09-06'),
('rab', '1991-03-06'),
('root', '2001-03-16') ;
insert into faculty(faculty_name) values
('kaka'),
('dope'),
('kallie'),
('kim');
insert into students_subject (subject_name, subject_faculty) values
('maths', 2),
('physics', 3),
('english', 4),
('biology', 1),
('statistics', 2),
('french', 4),
('economics',3);
insert into marks ( student_id, subject_id, marks) values
(1,1,70),
(1,2,60),
(1,3,98),
(1,4,75),
(1,5,90),
(1,6,30),
(1,7,40),
(2,1,70),
(2,2,60),
(2,3,70),
(2,4,105),
(2,5,95),
(2,6,30),
(2,7,10),
(3,1,70),
(3,2,60),
(3,3,70),
(3,4,75),
(3,5,99),
(3,6,30),
(3,7,10),
(4,1,70),
(4,2,60),
(4,3,70),
(4,4,89),
(4,5,99),
(4,6,30),
(4,7,19);
Я сам написал Query, чтобы разобраться с этим, но не могу его сломать.
select students.id, table_high.marks, table_high.faculty_name as high_faculty, table_high.subject_name as sub_high,
student_low.marks , student_low.faculty_name as faculty_low, student_low.subject_name as sub_low from students
inner join
(select students.id, students.student_name ,marks.marks, subject_joined.faculty_name, students_subject.subject_name from marks
inner join (select students_subject.id,students_subject.subject_name, faculty.faculty_name, students_subject.subject_faculty
from students_subject left join faculty on students_subject.subject_faculty = faculty.id)
as subject_joined on subject_joined.id = marks.subject_id
inner join faculty on subject_joined.subject_faculty = faculty.id
inner join students_subject on students_subject.id = marks.subject_id
inner join students on students.id = marks.student_id
order by 1, 3 desc) as table_high on table_high.id = students.id
inner join
(select students.id, students.student_name ,marks.marks, subject_joined.faculty_name, students_subject.subject_name from marks
inner join (select students_subject.id,students_subject.subject_name, faculty.faculty_name, students_subject.subject_faculty
from students_subject left join faculty on students_subject.subject_faculty = faculty.id)
as subject_joined on subject_joined.id = marks.subject_id
inner join faculty on subject_joined.subject_faculty = faculty.id
inner join students_subject on students_subject.id = marks.subject_id
inner join students on students.id = marks.student_id
order by 1, 3 ) as student_low on student_low.id = students.id
group by 1 ;
прикрепление экрана вывода:
