Longest Streak of Daily Orders | Dataford Interview Questions

Write a SQL query to find the length of the longest streak of consecutive days a customer ordered food on Zomato in the past year.

Asked in the Round 1: Technical stage. Use the customers and orders tables. For this exercise, treat the past year as 2024-01-01 through 2024-12-31.

Output

One row per customer, including customers with no qualifying orders.
Columns: customer_id, customer_name, and longest_streak_days.
Sort by customer_id ascending.

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique Zomato customer identifier
customer_name	VARCHAR(100)	Customer's display name

orders

Column	Type	Description
order_idPK	INT	Unique food order identifier
customer_id	INT	Customer who placed the order
order_date	DATE	Calendar date when the order was placed

Your question is Longest Streak of Daily Orders. Start with the requirements and the two tables in the Question tab.

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Problem