1097. Game Play Analysis V.sql

WITH install_dates AS(
SELECT player_id,MIN(event_date) AS install_date
FROM activity_1097
GROUP BY player_id
),
new AS(
SELECTi.player_id,i.install_date,a.event_date
FROM install_dates i
LEFT JOIN activity_1097 a ONi.player_id=a.player_idANDi.install_date+1=a.event_date
)

SELECT install_date,COUNT(player_id),ROUND(COUNT(event_date)::NUMERIC/COUNT(player_id),2)
FROM new
GROUP BY install_date;