Top Saved Pin Categories Query | Dataford Interview Questions

Pinterest wants to understand which Pin categories resonate most with users who recently joined the platform. Write a PostgreSQL query to find the three most-saved Pin categories among users whose Pinterest accounts were created in the last 30 days, using 2026-08-29 as the current date.

Requirements

Join users, pin saves, and Pins to connect signup cohorts with saved Pin categories.
Include users with signup_date from 2026-07-30 through 2026-08-29, inclusive. Exclude saves whose Pin has no category.
Count saves by category, rank categories by save count descending, and return the top three categories. Break ties alphabetically.

Schema

users

Column	Type	Description
user_idPK	INT	Pinterest user identifier
username	VARCHAR(100)	Display username
signup_date	DATE	Date the user created a Pinterest account

pins

Column	Type	Description
pin_idPK	INT	Pin identifier
title	VARCHAR(200)	Pin title
category	VARCHAR(80)	Content category assigned to the Pin

pin_saves

Column	Type	Description
save_idPK	INT	Save event identifier
user_id	INT	User who saved the Pin
pin_id	INT	Pin that was saved
saved_at	TIMESTAMP	Timestamp of the save event

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