title: Finding available timeslots in a day based on existing records in MySQL
body: <p>I have a table that has these fields:</p>
  
  <p><img src="https://i.stack.imgur.com/KjV0f.png" alt="enter image description here"></p>
  
  <p>How would I find all available time slots for that day (based on the day starting at 7am and ending at 10pm) that aren't currently in this table? For example, on one particular day, if all timeslots from 7am till 10pm were taken bar one at 6pm till 7pm, that would be the one result.</p>
  
  <p>The duration of each time slot does not vary - they all last one hour.</p>
  
  <p>I have tried many different things, but I have a feeling I am so far off, it is hardly worth posting what I've tried. </p>
  
  <p>Any help would be greatly appreciated!</p>