Select Top Customers Using Transaction Data Filters

Q: How do I practice SQL interview questions?

PracHub provides an interactive SQL console where you can write and test queries against real database schemas. Get instant feedback and compare your solution with the expected output.

Q: What difficulty level is this coding question?

This is a Medium difficulty Data Manipulation (SQL/Python) question, commonly asked during Technical Screen rounds at Amazon.

Q: What role is this question designed for?

This question is commonly asked for Data Scientist candidates at Amazon during technical interviews.

Question

transactions

+----+---------+------------+--------+
| id | user_id | order_date | amount |
+----+---------+------------+--------+
| 1  | 101     | 2023-01-01 | 120.50 |
| 2  | 102     | 2023-01-08 | 75.00  |
| 3  | 101     | 2023-02-02 | 200.00 |
| 4  | 103     | 2023-02-10 | 40.00  |
| 5  | 104     | 2023-03-12 | 150.00 |
+----+---------+------------+--------+

##### Scenario

Retail promotion targeting based on historical transaction data.

##### Question

Given a transactions table, select the customers who satisfy the provided campaign filters.

From those customers select exactly five with the highest total order count.

Explain how you would break ties if more than five customers meet the top-5 criterion.

##### Hints

Aggregate by customer, ORDER BY order_cnt DESC, LIMIT 5; add secondary sort (e.g., most recent order date or random) for deterministic tie-breaking.

PracHub · Accepted Answer

This question evaluates a candidate's ability to perform data aggregation, filtering, ranking, and deterministic tie-breaking on transactional datasets, assessing skills in Data Manipulation (SQL/Python).

Quick Overview

Select Top Customers Using Transaction Data Filters