AI Computer Science Academy · Faisalabad

SQL & Databases

Foreign keys

Task 40 of 56 SQL Section 4 · Changing data
All tasks
Read first Task 40

Foreign keys

A foreign key points at another table's primary key — like students.course_id.

Task

What does a foreign key do?

The editor already contains a starting point. Change it until every check passes — the Next task button unlocks when it does.

What you start with 
SELECT students.name, courses.title FROM students JOIN courses ON courses.id = students.course_id WHERE students.id = 4;
Syntax reference 
SELECT students.name, courses.title FROM students JOIN courses ON courses.id = students.course_id WHERE students.id = 4;

Read it, then write it yourself. Copy-paste teaches nothing.

The sample database 
CREATE TABLE courses (id INTEGER PRIMARY KEY, title TEXT, monthly_fee INTEGER);
CREATE TABLE students (id INTEGER PRIMARY KEY, name TEXT, city TEXT, course_id INTEGER, joined TEXT);
CREATE TABLE fees (id INTEGER PRIMARY KEY, student_id INTEGER, month TEXT, amount INTEGER, paid INTEGER);

INSERT INTO courses VALUES (1,'Web Design',9000),(2,'Python',11667),(3,'JavaScript',11667),(4,'AI & Prompt Engineering',15000);
INSERT INTO students VALUES
 (1,'Sara','Faisalabad',2,'2026-01-12'),
 (2,'Ali','Faisalabad',1,'2026-01-20'),
 (3,'Hina','Jhumra',2,'2026-02-02'),
 (4,'Bilal','Faisalabad',4,'2026-02-15'),
 (5,'Ayesha','Sargodha',3,'2026-03-01'),
 (6,'Usman','Jhumra',1,'2026-03-11'),
 (7,'Zainab','Faisalabad',4,'2026-04-05'),
 (8,'Hamza','Faisalabad',3,'2026-04-19');
INSERT INTO fees VALUES
 (1,1,'2026-01',11667,1),(2,1,'2026-02',11667,1),
 (3,2,'2026-01',9000,1),(4,2,'2026-02',9000,0),
 (5,3,'2026-02',11667,1),(6,3,'2026-03',11667,0),
 (7,4,'2026-02',15000,1),(8,4,'2026-03',15000,1),
 (9,5,'2026-03',11667,0),
 (10,6,'2026-03',9000,1),(11,6,'2026-04',9000,0),
 (12,7,'2026-04',15000,0),
 (13,8,'2026-04',11667,1);
SQL 1 automatic check Section 4 · Changing data
Code editor Ctrl + Enter runs 
Run your code to see the output and the checks.
Your result

Submit your code to see results

Write your code in the middle column and press Run code.

Checks on this task:

  • Check 1

Track progress

0 of 56 tasks complete

Next task unlocks when every check passes.

Sign in to keep your code and certificates.

Next task (pass every check first)