if this is an application for the 'real world', you need more tables
1. table to show start and end times of the working day and/or table to show contracted hours for each employee
2. table to record employee absences from the shop floor (holiday/sickness/training etc)
3. table to record what days are not working days (bank holidays/shutdowns etc)
not to mention employees should be in a separate table and this table should have a foreign key back to that table
Your requirement is complex and you appear to want a complete solution, but if you don't want to help us to help you, we can't do that
So best I can suggest is you investigate using subqueries or perhaps domain functions