title: Best way to handle business opening time in a year PHP and MySQL
body: <p>We have developed a website for pharmacies in which we show the opened pharmacies in a specific city.</p>
  
  <p>I handle this with a field named "timestamps" in wich it is stored all timestamps of opening hour every 15 minutes for a period of about 3 months.
  For example if every days the farmacy is open from 8:00 to 19:00 there is a range of timestamps from one time to another, with an interval of 15 minutes.</p>
  
  <p>While in the frontend we have a list of opened pharmacies and I could show opened ones by querying the database with for example:
  <code>"WHERE timestamps LIKE('%1449820800%')"</code> where the timestamp is the current time rounded to the nearest quarter hour.</p>
  
  <p><strong>The question is:</strong> considering the time ranges are different from week to week, is there a better way to handle this situation? Also because we have 25.000 users and the website is slow if we have large amount of timestamps.</p>
  
  <p>Thank you in advance!</p>