Question

I have 2 MySQL tables, ‘scheduled_time’ and ‘appointments’

‘scheduled_time’ has 2 DateTime fields, ‘start’ and ‘end’ – this is a time range of when I am available for appointments.

‘appointments’ contains appointment details but also a ‘start’ and ‘end’ field, this will ultimately be within the range specified in ‘scheduled_time’.

What is the best way for me to find empty time blocks when taking into account both tables?

Lets say I have ‘scheduled_time’ starting 11/9/2010 from 8am to 2pm. and I have one ‘appointment’ from 8am to 10am and one from 1pm to 2pm. How can I find the next available block of say 1 hour?

Answer 1

I did this a while ago. We had a similar structure:

• Available (contained all working hours for an employee, flexible working hours)
• Appointments (similar to yours)

What I did was basically this (steps):

• Get all start and end datetimes for employee < x >, sorted by startdate
• let startAvailable = start of the time search (in your case 11/9/2010 @ 8am)
• let appointment = first appointment in the list of appointments
• get the startdate of the first appointment. If the difference between these is big enough, there’s your block
• if not, let startAvailable = enddate of appointment
• remove appointment from the list, let appointment be the next appointment
• repeat the process of checking for an available block