MoM Active Sender Growth | Dataford Interview Questions

Write a SQL query to calculate the month-over-month growth rate of active senders in a specific geographic corridor at Remitly.

Use the United States to Mexico corridor and count a sender once per month when they have at least one completed transfer. Exclude pending, failed, canceled, and invalid-corridor transfers.

Output

One row per month with activity in the selected corridor.
Columns: month, active_senders, and mom_growth_rate_pct.
Calculate growth as a percentage versus the prior month. Return NULL when no prior month exists, and order chronologically.

Schema

transfers

Column	Type	Description
transfer_idPK	INT	Unique transfer identifier
sender_id	INT	Identifier of the sender who initiated the transfer
corridor_id	INT	Geographic corridor identifier
sent_at	TIMESTAMP	Timestamp when the transfer was initiated
status	VARCHAR(20)	Transfer processing status

corridors

Column	Type	Description
corridor_idPK	INT	Unique corridor identifier
origin_country	VARCHAR(80)	Country where the transfer originates
destination_country	VARCHAR(80)	Country receiving the transfer

Your question is MoM Active Sender Growth. Start with the requirements and the two tables 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.

Problem