[SQL]LeetCode Game Play Analysis IV

✅ 코드

WITH T AS (
    SELECT player_id
        , MIN(event_date) AS first_log
    FROM Activity
    GROUP BY player_id
)

SELECT ROUND(COUNT(DISTINCT T.player_id) / COUNT(DISTINCT A.player_id), 2) AS fraction
FROM Activity AS A
   LEFT JOIN T ON A.player_id = T.player_id
             AND A.event_date = DATE_ADD(T.first_log, INTERVAL 1 DAY)

WITH문으로 유저별 첫 로그인 일자를 모아둔 테이블을 생성했습니다.

이후 Activity 테이블과 특정 조건을 만족하는 LEFT JOIN을 수행했습니다.