How to check if a DateTime range is within another 3 month DateTime range

Question

Hi I have a Start Date and End Date per record in a db.

I need to check to see where the time period falls in a 2 year period broken into two lots of quarters then d

Answer 1

If you want to compare two dates you should find out the first day of the quarter corresponds every of this dates, then you can compare this two dates:

using System;

namespace DataTime {
    class Program {
        static int GetQuarter (DateTime dt) {
            int Month = dt.Month;   // from 1 to 12
            return Month / 3 + 1;
        }
        static DateTime GetQuarterFirstDay (DateTime dt) {
            int monthsOfTheFirstDayOfQuarter = (GetQuarter (dt) - 1) * 3 + 1;
            return new DateTime(dt.Year, monthsOfTheFirstDayOfQuarter, 1);
            // it can be changed to
            //  return new DateTime(dt.Year, (dt.Month/3)*3 + 1, 1);
        }
        static void Main (string[] args) {
            DateTime dt1 = new DateTime (2009, 6, 9),
                     dt2 = new DateTime (2009, 7, 9),
                     dt3 = new DateTime (2009, 8, 9),
                     dt4 = new DateTime (2009, 8, 9);

            Console.WriteLine ("dt1={0}", dt1.AddMonths (1));
            Console.WriteLine ("dt2={0}", dt2.AddMonths (1));
            Console.WriteLine ("dt3={0}", dt3.AddMonths (1));

            DateTime startDate = DateTime.Now,
                     endDate1 = startDate.AddMonths(24).AddDays(1),
                     endDate2 = startDate.AddMonths(24).AddDays(-1),
                     endDate3 = startDate.AddMonths(28);
            Console.WriteLine ("Now we have={0}", startDate);
            Console.WriteLine ("endDate1={0}", endDate1);
            Console.WriteLine ("endDate2={0}", endDate2);
            Console.WriteLine ("endDate3={0}", endDate3);

            Console.WriteLine ("GetQuarterFirstDay(startDate)={0}", GetQuarterFirstDay (startDate));
            Console.WriteLine ("GetQuarterFirstDay(endDate1)={0}", GetQuarterFirstDay (endDate1));
            Console.WriteLine ("GetQuarterFirstDay(endDate2)={0}", GetQuarterFirstDay (endDate2));
            Console.WriteLine ("GetQuarterFirstDay(endDate3)={0}", GetQuarterFirstDay (endDate3));
            if (DateTime.Compare (GetQuarterFirstDay (endDate2), GetQuarterFirstDay (startDate).AddMonths (24)) > 0)
                Console.WriteLine ("> 2 Yeas");
            else
                Console.WriteLine ("<= 2 Yeas");
            if (DateTime.Compare (GetQuarterFirstDay (endDate3), GetQuarterFirstDay (startDate).AddMonths (24)) > 0)
                Console.WriteLine ("> 2 Yeas");
            else
                Console.WriteLine ("<= 2 Yeas");
        }
    }
}

produce

dt1=09.07.2009 00:00:00
dt2=09.08.2009 00:00:00
dt3=09.09.2009 00:00:00
Now we have=22.04.2010 11:21:45
endDate1=23.04.2012 11:21:45
endDate2=21.04.2012 11:21:45
endDate3=22.08.2012 11:21:45
GetQuarterFirstDay(startDate)=01.04.2010 00:00:00
GetQuarterFirstDay(endDate1)=01.04.2012 00:00:00
GetQuarterFirstDay(endDate2)=01.04.2012 00:00:00
GetQuarterFirstDay(endDate3)=01.07.2012 00:00:00
<= 2 Yeas
> 2 Yeas

EDITED: I fixed an error from the first version. Now it should works correct.