MS SQL Solution faster 99%~
\nselect event_day as day,emp_id,sum(out_time)-sum(in_time) as total_time from Employees group by event_day,emp_id\n
```\nselect event_day as day,emp_id,sum(out_time)-sum(in_time) as total_time from Employees group by event_day,emp_id\n```
['MS SQL Server']