MySQL solution without joining
\n# Write your MySQL query statement below\nselect (\n    round(\n        (\n            select count(distinct player_id)\n            from Activity\n          
```\n# Write your MySQL query statement below\nselect (\n    round(\n        (\n            select count(distinct player_id)\n            from Activity\n            where (player_id, event_date) in (\n                select player_id,\n                    DATE_ADD(min(event_date), interval 1 day) as second_login\n                from Activity\n                group by player_id)\n        ) / \n        (\n            select count(distinct player_id)\n            from Activity\n        )\n    , 2)\n) as fraction\n\n```
[]