My first instinct was to just join everything and group by both event_type and plan_type at once, which felt cleaner but actually makes the logic murky.
First, identify the single most popular event type by counting occurrences in the events table. Then, join the events table with the users table to get the plan type for each event, and count how many times each plan type is associated with that top event type. Finally, return the plan type with the highest count.
Pro tip: Clarify assumptions about ties and data freshness upfront, and mention that you'd validate the result with a quick sanity check (e.g., comparing counts to overall plan distribution) to ensure the association isn't just due to a popular plan.
Write a subquery or CTE that groups the events table by event_type and counts occurrences, then orders descending and limits to 1 to get the top event type.
Join the events table to the users table on user_id to associate each event with the user's plan type.
Apply a WHERE clause to keep only rows where event_type equals the top event type identified in step 1.
Group the filtered results by plan_type, count the number of events per plan, order descending, and limit to 1 to get the plan type most associated with the top event.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.