Determine Maximum Consecutive Order Days Per User
Company: Netflix
Role: Data Scientist
Category: Data Manipulation (SQL/Python)
Difficulty: medium
Interview Round: Onsite
orders
+----+---------+------------+
| id | user_id | order_date |
+----+---------+------------+
| 1 | 101 | 2024-01-01 |
| 2 | 101 | 2024-01-02 |
| 3 | 101 | 2024-01-05 |
| 4 | 102 | 2024-01-03 |
| 5 | 102 | 2024-01-04 |
+----+---------+------------+
##### Scenario
The commerce team wants to know each customer’s best ordering streak for loyalty analysis.
##### Question
For every user, return the maximum number of consecutive calendar days on which they placed at least one order.
##### Hints
Generate dense date series per user; use gaps-and-islands or window functions.
Quick Answer: Determine Maximum Consecutive Order Days Per User evaluates SQL or pandas logic, joins, grouping, window functions, null handling, edge cases, and validation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.