Ad Campaign Funnel Analysis

SQLMediumMid levelMeta~15 min

Problem

**[Asked at Facebook/Meta]**

A digital ad campaign tracks users through three stages: they see an impression,
some click, and some then sign up. For each stage, calculate:
1. How many distinct users reached that stage
2. What percentage of the **previous stage** converted (drop-off rate)

Use these stage labels in order: `impression` → `click` → `signup`.
Return `stage`, `user_count`, and `pct_of_prev` (NULL for the first stage, rounded to 1 dp for others).

Tables

Example rows — the live problem includes the full dataset.

funnel_events

event_id	user_id	stage	event_date

Expected output

Your answer should return 3 rows with the columns stage, user_count, pct_of_prev.

Starter code (SQL)

SELECT *
FROM funnel_events;

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