LeetCode题解(1097)：游戏玩法分析V(SQL)

题目：原题链接（困难）

标签：SQL

解法	时间复杂度	空间复杂度	执行用时
Ans 1 (Python)			437ms (34.01%)
Ans 2 (Python)
Ans 3 (Python)

解法一：

SELECT A1.install_dt,
       COUNT(A1.player_id) AS installs,
       round(COUNT(a2.player_id) / COUNT(a1.player_id), 2) AS Day1_retention
FROM (
         SELECT player_id, MIN(event_date) AS install_dt
         FROM Activity
         GROUP BY player_id
     ) AS A1
         LEFT JOIN
     Activity AS A2 ON (A1.player_id = A2.player_id AND A2.event_date = A1.install_dt + 1)
GROUP BY A1.install_dt;