title: PHP and MYSQL time related query
body: <p>I am developing a web application in which remainders will be sent to subscribers at a particular time of the day. Let's say a person John fills a form and asks to send email remainder at 12 pm every day. I have developed a cron job for this purpose but I am having issues related to time. Here is my problem if John is from USA then the email have to be sent according to US time and so on. Now I use MYSQL to store the time zone and Time from each person. But How do I schedule the emails according to specific time zone. My server time is set to UTC. So if a person has time zone of GMT +5 how many hours I have to add in the UTC so that emails should be sent at correct time.<br>
  I don't need the code just give me a common formula to calculate the correct time of email.
  Thanks a lot,
  Ahmar.</p>