[ MySQL ] SOLUTION
\nselect\n    event_day as day,\n    emp_id,\n    sum(out_time - in_time) as total_time\nfrom Employees\ngroup by 1, 2\norder by 1;\n
```\nselect\n    event_day as day,\n    emp_id,\n    sum(out_time - in_time) as total_time\nfrom Employees\ngroup by 1, 2\norder by 1;\n```
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