Top 5 Users Per Category | Dataford Interview Questions

Given a table of user activity, how would you identify the top 5 users per category?

Use the provided users and user_activity tables. Treat the number of activity records as each user's activity total. Exclude rows with a NULL category. Break ties by ascending user_id.

Output

One row per selected user and category, with columns category, user_id, user_name, activity_count, and category_rank.
Include at most five users per category, ordered by category, category_rank, and user_id.

Schema

users

Column	Type	Description
user_idPK	INT	Unique user identifier
user_name	VARCHAR(100)	Display name of the user

user_activity

Column	Type	Description
activity_idPK	INT	Unique activity record identifier
user_id	INT	User who generated the activity
category	VARCHAR(50)	Activity category
activity_at	TIMESTAMP	Timestamp when the activity occurred

Your question is Top 5 Users Per Category. Start with the requirements and the two tables in the Question tab.

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Problem