SQL practice questions

Browse 20 practice questions and their starter queries. Query execution, submissions and progress tracking are currently unavailable.

Read each problem, identify the columns and tables you need, then work through the starter query. For guided learning, explore the Data Analyst SQL curriculum and portfolio projects.

All students

Easy

Return every row from the students table.

Starter SQL

SELECT * FROM students;

High scorers

Easy

Find score rows where score is at least 90.

Starter SQL

SELECT * FROM scores
WHERE score >= 90;

Top scores first

Easy

Return all scores ordered from highest to lowest.

Starter SQL

SELECT * FROM scores
ORDER BY score DESC;

Students in Delhi

Easy

Return students who live in Delhi.

Starter SQL

SELECT * FROM students
WHERE city = 'Delhi';

Uppercase student names

Easy

Return each student name in uppercase using a string function.

Starter SQL

SELECT UPPER(name) AS name_upper
FROM students;

Student course titles

Medium

List each student name with module and score by joining students to scores.

Starter SQL

SELECT s.name, sc.module, sc.score
FROM students s
JOIN scores sc ON sc.student_id = s.id;

Average score by module

Medium

For each module, return the average score.

Starter SQL

SELECT module, AVG(score) AS avg_score
FROM scores
GROUP BY module;

Modules with high averages

Medium

Return modules whose average score is above 85.

Starter SQL

SELECT module, AVG(score) AS avg_score
FROM scores
GROUP BY module
HAVING AVG(score) > 85;

Above class average

Hard

Return students whose score is above the overall average (use a subquery).

Starter SQL

SELECT s.name, sc.score
FROM students s
JOIN scores sc ON sc.student_id = s.id
WHERE sc.score > (
  SELECT AVG(score) FROM scores
);

Pass or fail label

Medium

Label each score as Pass (>= 60) or Fail using CASE.

Starter SQL

SELECT student_id, score,
  CASE WHEN score >= 60 THEN 'Pass' ELSE 'Fail' END AS result
FROM scores;

Rank scores

Hard

Rank scores within each module using a window function.

Starter SQL

SELECT module, student_id, score,
  RANK() OVER (PARTITION BY module ORDER BY score DESC) AS rank_in_module
FROM scores;

Top scorer per module

Hard

Use a CTE to list the highest score in each module.

Starter SQL

WITH max_scores AS (
  SELECT module, MAX(score) AS top_score
  FROM scores
  GROUP BY module
)
SELECT * FROM max_scores;

Customers in Jaipur

Easy

Return customers who live in Jaipur.

Starter SQL

SELECT * FROM customers
WHERE city = 'Jaipur';

Product catalog

Easy

List product name and price for every product.

Starter SQL

SELECT name, price FROM products;

Order lines

Medium

Show customer name, product name, quantity, and order_date for each order.

Starter SQL

SELECT c.name AS customer, p.name AS product, o.quantity, o.order_date
FROM orders o
JOIN customers c ON c.id = o.customer_id
JOIN products p ON p.id = o.product_id;

Products starting with N

Easy

Find products whose name starts with the letter N.

Starter SQL

SELECT name, price
FROM products
WHERE name LIKE 'N%';

All patients

Easy

Return every row from the patients table.

Starter SQL

SELECT * FROM patients;

Patients in Toronto

Easy

List patients who live in Toronto.

Starter SQL

SELECT * FROM patients
WHERE city = 'Toronto';

Patient admissions

Medium

Show each patient's first name, last name, admission date, and diagnosis.

Starter SQL

SELECT p.first_name, p.last_name, a.admission_date, a.diagnosis
FROM patients p
JOIN admissions a ON a.patient_id = p.patient_id;

Admissions per doctor

Medium

Count admissions handled by each doctor (show doctor_id and total).

Starter SQL

SELECT attending_doctor_id, COUNT(*) AS admission_count
FROM admissions
GROUP BY attending_doctor_id;