WITH dataset AS ( SELECT user_pseudo_id, event_name, PARSE_DATE(‘%Y%m%d’, event_date) AS event_date, TIMESTAMP_MICROS(event_timestamp) AS event_timestamp FROM `bigquery-public-data.ga4_obfuscated_sample_ecommerce.events_202101*` WHERE event_name IN (‘view_item’, ‘add_to_cart’, ‘begin_checkout’, ‘purchase’) ), 

view_item AS ( SELECT user_pseudo_id, event_date, event_timestamp FROM dataset WHERE event_name = ‘view_item’ ), 

add_to_cart AS ( SELECT user_pseudo_id, event_date, event_timestamp FROM dataset WHERE event_name = ‘add_to_cart’ ), 

begin_checkout AS ( SELECT user_pseudo_id, event_date, event_timestamp FROM dataset WHERE event_name = ‘begin_checkout’ ), 

purchase AS ( SELECT user_pseudo_id, event_date, event_timestamp FROM dataset WHERE event_name = ‘purchase’ ), 

funnel AS ( SELECT vi.event_date, COUNT(DISTINCT vi.user_pseudo_id) AS view_item, COUNT(DISTINCT atc.user_pseudo_id) AS add_to_cart, COUNT(DISTINCT bc.user_pseudo_id) AS begin_checkout, COUNT(DISTINCT p.user_pseudo_id) AS purchase FROM view_item vi LEFT JOIN add_to_cart atc ON vi.user_pseudo_id = atc.user_pseudo_id AND vi.event_date = atc.event_date AND vi.event_timestamp < atc.event_timestamp LEFT JOIN begin_checkout bc ON atc.user_pseudo_id = bc.user_pseudo_id AND atc.event_date = bc.event_date AND atc.event_timestamp < bc.event_timestamp LEFT JOIN purchase p ON bc.user_pseudo_id = p.user_pseudo_id AND bc.event_date = p.event_date AND bc.event_timestamp < p.event_timestamp GROUP BY 1 ) 

SELECT event_date, view_item, add_to_cart, begin_checkout, purchase, 1 AS view_item_rate, ROUND(COALESCE(add_to_cart / NULLIF(view_item,0), 0), 2) AS add_to_cart_rate, ROUND(COALESCE(begin_checkout / NULLIF(view_item,0), 0), 2) AS begin_checkout_rate, ROUND(COALESCE(purchase / NULLIF(view_item,0), 0), 2) AS purchase_rate 

FROM funnel 

ORDER BY 1 ASC