在SQL PHP中重复日历事件

Question

I have a loop that loops through all the days in a given month that a person can create events from a start date/time and specify an ending date/time. I am incorporating where events can be repeated every xx days, xx months or xx years.

I have no idea how to match up the current day in the loop to see if the repeating has started. Say I had the event "Pickup Silver" that was 3 days long. I want this to happen every 7 days starting on the 2nd. The calendar should show this event every 7 days from the starting date/time. Starting on the days 2,9,16,30 and so on.

#Loop starts and math calulates the current unix start of each day
##The SQL QUERY to lookup if there are any events starting or ending on this day 
#$SQL =" 
#SELECT
# Name as OutputTitle,
# ID
# FROM
#safe_calendar
#WHERE
#AutherID = '[AccountID]'
#AND
#AutherTable = '[TableName]'
#AND
#(UnixFrom - 86400) <  [UnixThisDay] 
#AND
#UnixEnd >= [UnixThisDay]
#";

Answer 1

I would suggest taking a look at iCalendar RRULEs . If you are doing a pretty basic recurrence pattern, then don't bother with the bulk of this because it's quite large but very comprehensive. This will at least give you a good idea, that is a standard, on how to structure your data and what you need to store. Specifically, in your case, it sounds like you'd need to store the start and end date of the recurrence as well as the start date and length of the event. From that, you can deduce if your current day intersects with a recurrence day.

Something to keep in mind is calendar calculations are actually quite difficult. You need to account for timezone differences, daylight savings (not only on what days but how to deal with the extra or missing hour), leap years, etc. Even what appears to be simple can become quite complex if you factor in all the outlier situations.