Daily Conversion Rate SQL | Dataford Interview Questions

Your question is Daily Conversion Rate SQL. Start with the requirements and the two tables on the right.

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Problem

Grow Therapy wants to monitor how effectively daily user sessions lead to bookings. Write a PostgreSQL query that calculates the conversion rate for each calendar day.

Requirements

Treat each distinct user with a session on a day as one daily session user.
Count a user as converted when they have at least one Grow Therapy booking on the same calendar day.
Use a LEFT JOIN so days with no conversions remain in the output, and calculate conversion as a percentage rounded to two decimal places.
Return results in ascending date order.

Schema

sessions

Column	Type	Description
session_idPK	BIGINT	Unique session identifier
user_id	BIGINT	Grow Therapy user identifier
started_at	TIMESTAMPTZ	Session start timestamp

bookings

Column	Type	Description
booking_idPK	BIGINT	Unique booking identifier
user_id	BIGINT	User who made the booking
booked_at	TIMESTAMPTZ	Booking creation timestamp