I have a booking page where users can book some event which have multiple days (for example movie can be shown on 3 days). Now I modified creation date in K2 and saved there the first upcoming day for that movie when it will be shown. Than I am reading from K2 category Movies creation date days for the K2 blog calendar. The problem is that 1 movie is just one article and therefore I save only 1st upcoming day, when 2 rest are missing. I need the rest of 2 to be also shown in K2 blog calendar. So I thought to make a new table in the database just with the days and read it with K2 blog calendar, is it possible to read the data from another table (not K2) and fetch it in calendar? Or any other suggestion would be appreciated :)

Hello Julie, I think you should look for an extension that offers this functionality.
You can look at the JED or at the extend K2 section of this site.

FYI. This extension is pretty popular: extensions.joomla.org/extensions/extension-specific/k2-extensions/22377

Thank you a lot. I have already found another plugin in JED, this one:

extensions.joomla.org/extensions/calendars-a-events/events/events-calendars/11396

I have changed the javascript and ajax request, removed the things I dont need like pop-up, event listeners, etc. Now is working everything fine. Maybe a good thing in future would be to implement something like what I needed, a table with dates, M:N relation or at least 1:N with foreign key of an article and related dates to this article. But if someone needs something like this what I had earlier, to save the first upcoming event in creation date and show it in K2 blog calendar that is a fine solution, and of course run the cron-job script every day to update the field with upcoming events.

Thank you for your feedback.
This sounds like an interesting module indeed. We will consider it.