🚀 Simple MySQL solution Without using JOIN ✅
Code☝🏻upvote if you find my solution useful❗
# Code
```mysql []
# Write your MySQL query statement below
SELECT ROUND(COUNT(DISTINCT player_id) / (SELECT COUNT(DISTINCT player_id) FROM Activity), 2) as fraction
FROM Activity
WHERE (player_id, DATE_SUB(event_date, INTERVAL 1 DAY))
IN (SELECT player_id, MIN(event_date) AS first_login FROM ACTIVITY GROUP BY player_id)
```

## ☝🏻upvote if you find my solution useful❗
['MySQL']