5. Event funnel by stage
Asked in screens shaped like: Meta, Snap, Pinterest
Product wants funnel volume per stage: how many events fired and how many distinct customers reached each one. Total events overstates reach because one customer can fire the same event repeatedly.
Requirements
- Columns: event_name, events, customers
- Only event_name in ('page_view', 'add_cart', 'purchase')
- events counts rows; customers counts distinct customer_id
- Order by customers descending, then event_name
Expected output
event_name, events, customers
Row order is graded, so ORDER BY matters here.
Tables this problem reads. The full warehouse is available in thesandbox.
events
~400 rows
Clickstream. payload is raw JSON — use json_extract on it.
- event_idINTEGER
- customer_idTEXT
- event_nameTEXT— page_view, add_cart, purchase, search
- occurred_atTEXT
- payloadTEXT— {"source":"web|ios","campaign":"c0…c4"}
Pick a warehouse dialect above the editor. The engine is still SQLite; common syntax is rewritten before it runs.
SQLite cheat sheet
- Truncate to day
DATE(ordered_at) - Current date
DATE('now') - Conditional
CASE WHEN … THEN … ELSE … END - String aggregate
GROUP_CONCAT(col, ", ") - JSON field
json_extract(payload, '$.source') - Date difference
JULIANDAY(a) - JULIANDAY(b) - Filter a window
CTE, then WHERE rn = 1 - Median
ROW_NUMBER + COUNT(*) OVER ()
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