calculating opening appointments

[lakke2120]

Hello,

I have one pivot column of dates that represents doctor scheduled appointments and another pivot column that show appointment times. Since the data only shows scheduled appointments, it does not show the available time each day that are available for open appointments or time in between scheduled appointments.

I need to show the third available appointment day, which is to calculate what the third day, starting from the first date, that a doctor has an appointment slot available. thank you. Any help would be greatly appreciated

[TABLE="class: grid, width: 500"]
<tbody>[TR]
[TD]Facility[/TD]
[TD]Doctor[/TD]
[TD]appointment start time[/TD]
[TD]2/19/18[/TD]
[TD]2/20/18[/TD]
[TD]2/21/18[/TD]
[TD]2/22/18[/TD]
[/TR]
[TR]
[TD]PV[/TD]
[TD]Jones[/TD]
[TD]8:30 am[/TD]
[TD]1[/TD]
[TD]1[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]10:30[/TD]
[TD]1[/TD]
[TD][/TD]
[TD]1[/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]10:45[/TD]
[TD]1[/TD]
[TD]1[/TD]
[TD][/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]11:30[/TD]
[TD][/TD]
[TD][/TD]
[TD]1[/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]1:00[/TD]
[TD]1[/TD]
[TD][/TD]
[TD]1[/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]1:15[/TD]
[TD]1[/TD]
[TD][/TD]
[TD][/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD]1:45[/TD]
[TD]1[/TD]
[TD][/TD]
[TD][/TD]
[TD]1[/TD]
[/TR]
</tbody>[/TABLE]