Month-over-Month Paid Search Growth | Dataford Interview Questions

Write a query to calculate the month-over-month growth rate of website signups originating from paid search campaigns at Redfin.

Use the provided signup and campaign data. Include only months with at least one signup attributed to a paid search campaign. Return a NULL growth rate for the first included month.

Output

One row per month, ordered chronologically.
Columns: month_start, signup_count, and mom_growth_rate.
Report mom_growth_rate as a percentage rounded to two decimal places.

Schema

website_signups

Column	Type	Description
signup_idPK	INT	Unique identifier for the website signup
signed_up_at	TIMESTAMP	Timestamp when the signup occurred
campaign_id	INT	Campaign attributed to the signup

marketing_campaigns

Column	Type	Description
campaign_idPK	INT	Unique identifier for a marketing campaign
campaign_name	VARCHAR(100)	Marketing campaign name
channel	VARCHAR(50)	Acquisition channel for the campaign

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