Rolling Spend SQL Query | Dataford Interview Questions

Given a table of transaction logs, write a query to calculate the total spend per user over a rolling 30-day window.

Treat each transaction date as the end of its window. Include that date and the preceding 29 calendar days. Treat NULL transaction amounts as zero.

Output

One row per transaction, with user_id, transaction_time, transaction_id, and rolling_30_day_spend.
Include all transactions and sort by user_id, transaction_time, and transaction_id ascending.

transaction_logs

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
user_id	INT	User who made the transaction
transaction_time	TIMESTAMP	Timestamp when the transaction occurred
amount	NUMERIC(12,2)	Transaction amount

Your question is Rolling Spend SQL Query. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Given a table of transaction logs, write a query to calculate the total spend per user over a rolling 30-day window.

Treat each transaction date as the end of its window. Include that date and the preceding 29 calendar days. Treat NULL transaction amounts as zero.

One row per transaction, with user_id, transaction_time, transaction_id, and rolling_30_day_spend.
Include all transactions and sort by user_id, transaction_time, and transaction_id ascending.

transaction_logs

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
user_id	INT	User who made the transaction
transaction_time	TIMESTAMP	Timestamp when the transaction occurred
amount	NUMERIC(12,2)	Transaction amount

Your question is Rolling Spend SQL Query. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.