Aarni Ruuhimäki wrote:
> Thanks Frank,
> 
>>> a    start_day before period_start, end_day before period_start
> 
> This I don't have to care about as it is not in the period we are looking at.
> 
>>> b    start_day = period_start, end_day = period_start
> 
> Is zero days/nights, ignored. Not even possible to insert in the application. 
> end_day must be greater than start_day.
You should still consider rows that are "out of range" or "zero nights" 
in your test cases to make sure your report processes them correctly.