SQL challenges

Practice problem statements with input format, output format, constraints and solutions.

beginner

SQL Introduction challenge

Build a small solution that uses SQL Introduction in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 50
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core sql introduction pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 50
ORDER BY total DESC;

beginner

SELECT challenge

Build a small solution that uses SELECT in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 51
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core select pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 51
ORDER BY total DESC;

beginner

WHERE challenge

Build a small solution that uses WHERE in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 52
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core where pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 52
ORDER BY total DESC;

beginner

ORDER BY challenge

Build a small solution that uses ORDER BY in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 53
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core order by pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 53
ORDER BY total DESC;

beginner

LIMIT challenge

Build a small solution that uses LIMIT in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 54
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core limit pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 54
ORDER BY total DESC;

beginner

INSERT challenge

Build a small solution that uses INSERT in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

INSERT INTO orders (customer, total, status)
VALUES ('Asha', 55, 'paid');

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core insert pattern before polishing the final output.

Solution

INSERT INTO orders (customer, total, status)
VALUES ('Asha', 55, 'paid');

beginner

UPDATE challenge

Build a small solution that uses UPDATE in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

UPDATE orders
SET status = 'refunded'
WHERE id = 42 AND status = 'paid';

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core update pattern before polishing the final output.

Solution

UPDATE orders
SET status = 'refunded'
WHERE id = 42 AND status = 'paid';

beginner

DELETE challenge

Build a small solution that uses DELETE in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT customer, total, status
FROM orders
WHERE total >= 57
ORDER BY total DESC;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core delete pattern before polishing the final output.

Solution

SELECT customer, total, status
FROM orders
WHERE total >= 57
ORDER BY total DESC;

beginner

GROUP BY challenge

Build a small solution that uses GROUP BY in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT status, COUNT(*) AS orders, SUM(total) AS revenue
FROM orders
GROUP BY status
HAVING SUM(total) >= 58;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core group by pattern before polishing the final output.

Solution

SELECT status, COUNT(*) AS orders, SUM(total) AS revenue
FROM orders
GROUP BY status
HAVING SUM(total) >= 58;

beginner

HAVING challenge

Build a small solution that uses HAVING in SQL and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

SELECT status, COUNT(*) AS orders, SUM(total) AS revenue
FROM orders
GROUP BY status
HAVING SUM(total) >= 59;

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core having pattern before polishing the final output.

Solution

SELECT status, COUNT(*) AS orders, SUM(total) AS revenue
FROM orders
GROUP BY status
HAVING SUM(total) >= 59;