如何使用特定的关键条件 Entity Framework Core 3.1 检查（从日期+时间到日期+时间）

Question

When the user create a meet I need to check if this room is reserved between two datetime ( From DateTime , To DateTime ) and if it is reserved return back to the same page with display message.

I tried to check the datatime between two periods (from datetime - to datetime) in specific place when user tried to create a meeting, system check between (from datetime - to datetime) if there any datetime between these period, system will send message to user, tell user that you can't create meeting, sense there is meeting exist in the place, but I am stuck for two days.

I tried to apply these solution below, but, it's work for some cases and other cases give me failure:

First Solution I Applied:

if (db.Meetings.Any(x => x.POMId == meetings.POMId && x.MeetingDateFrom <= meetings.MeetingDateFrom && x.MeetingDateTo >= meetings.MeetingDateTo))
{
    TempData["message"] = "This date time (From Date: " + meetings.MeetingDateFrom.ToString("dd MMMM yyyy hh:mm tt") + ", To Date: " + meetings.MeetingDateTo.ToString("dd MMMM yyyy hh:mm tt") + ") in the " + placeOfMeeting + " is already booked";
    TempData["color"] = "warning";
    return RedirectToAction(nameof(Create));
}

Second Solution I Applied:

if (db.Meetings.Any(x => x.POMId == meetings.POMId && x.MeetingDateFrom >= meetings.MeetingDateFrom && x.MeetingDateTo <= meetings.MeetingDateTo))
{
    TempData["message"] = "This date time (From Date: " + meetings.MeetingDateFrom.ToString("dd MMMM yyyy hh:mm tt") + ", To Date: " + meetings.MeetingDateTo.ToString("dd MMMM yyyy hh:mm tt") + ") in the " + placeOfMeeting + " is already booked";
    TempData["color"] = "warning";
    return RedirectToAction(nameof(Create));
}

Third Solution I Applied:

if (db.Meetings.Any(x => x.POMId == meetings.POMId && ((x.MeetingDateFrom <= meetings.MeetingDateFrom && x.MeetingDateTo >= meetings.MeetingDateTo) || (x.MeetingDateFrom >= meetings.MeetingDateFrom && x.MeetingDateTo <= meetings.MeetingDateTo))))
{
    TempData["message"] = "This date time (From Date: " + meetings.MeetingDateFrom.ToString("dd MMMM yyyy hh:mm tt") + ", To Date: " + meetings.MeetingDateTo.ToString("dd MMMM yyyy hh:mm tt") + ") in the " + placeOfMeeting + " is already booked";
    TempData["color"] = "warning";
    return RedirectToAction(nameof(Create));
}

But all these solutions go through failure when testing.

The question is:

How you check between two date+time (from datetime - to datetime) using specific key (place, reserve, etc...) if exist in database table or not?

Answer 1

After applying many test cases in more than 4 days work, I find the solution for this case and applied, and it is working perfectly.

Solution for this case is:

if (db.Meetings.Any(x => x.POMId == meetings.POMId && x.MeetingDateTo >= meetings.MeetingDateFrom && x.MeetingDateFrom <= meetings.MeetingDateTo))
{
    TempData["message"] = "This date time (From Date: " + meetings.MeetingDateFrom.ToString("dd MMMM yyyy hh:mm tt") + ", To Date: " + meetings.MeetingDateTo.ToString("dd MMMM yyyy hh:mm tt") + ") in the " + placeOfMeeting + " is already booked";
    TempData["color"] = "warning";
    return RedirectToAction(nameof(Create));
}

Explanation:

You will check if the (New From Date <= All To Date from DB) && (New To Date >= All From Date from DB)