Window Functions | Dataford Interview Questions

What are window functions? What is partition by?

Asked in the data analyst panel stage. Demonstrate the answer using the provided transactions table.

Output

Return one row per transaction with transaction_id, cardholder_id, transaction_date, amount, transaction_number, and cardholder_total.
Number transactions independently for each cardholder by date and transaction ID, and show each cardholder's total amount.
Sort by cardholder_id ascending with null cardholders last, then transaction date and transaction ID.

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
cardholder_id	INT	Cardholder identifier
transaction_date	DATE	Date of the transaction
amount	DECIMAL(10,2)	Transaction amount

Your question is Window Functions. 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.

What are window functions? What is partition by?

Asked in the data analyst panel stage. Demonstrate the answer using the provided transactions table.

Return one row per transaction with transaction_id, cardholder_id, transaction_date, amount, transaction_number, and cardholder_total.
Number transactions independently for each cardholder by date and transaction ID, and show each cardholder's total amount.
Sort by cardholder_id ascending with null cardholders last, then transaction date and transaction ID.

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
cardholder_id	INT	Cardholder identifier
transaction_date	DATE	Date of the transaction
amount	DECIMAL(10,2)	Transaction amount

Your question is Window Functions. 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.