Simple MySQL solution, BEAT 99%
\nSELECT ROUND(SUM(CASE WHEN a.event_date + 1 = b.event_date THEN 1 ELSE 0 END)/COUNT(DISTINCT a.player_id), 2) AS fraction \nFROM (SELECT player_id, MIN(event_
```\nSELECT ROUND(SUM(CASE WHEN a.event_date + 1 = b.event_date THEN 1 ELSE 0 END)/COUNT(DISTINCT a.player_id), 2) AS fraction \nFROM (SELECT player_id, MIN(event_date) AS event_date\n      FROM Activity \n      GROUP BY player_id) AS a JOIN Activity AS b \nON a.player_id = b.player_id  \n```
[]