4 Replies Latest reply on Jun 14, 2015 8:19 AM by wannab0133

    convert datetime to decimal


      Does anyone know of a way to convert a datetime (like 2015-06-10 07:30:00) to a decimal, similar to:

      42165.450 where 42165 is days and 450 is minutes?  If I try the following:


      <cfset dtNow = "2015-06-10" />


      <cfset dtOne = CreateDateTime(

          Year( dtNow ),

          Month( dtNow ),

          Day( dtNow ),

          07, <!--- 6 PM. --->

          30, <!--- 30 Minutes. --->

          00 <!--- 0 Seconds. --->

          ) />


      <!--- Dump out result. --->

      <cfdump var="#NumberFormat(dtone,'99999.99999')#" /><br>


      I end up with 42165.31250


        • 1. Re: convert datetime to decimal
          BKBK Adobe Community Professional & MVP

          There is actually no such thing as a conversion of a date to a number of days. Methods like #NumberFormat(dtone,'99999.99999')# or #dtone+0# are unofficial.


          The proper way to do it is to convert a time period into days. So you first have to define your 'zero' date.


          In Coldfusion, the zero date is 12 A.M., December 30, 1899. But it is usually, rather confusingly, given the value createdatetime(1899,12,29,12,0,0). Hence.


          <cfset cfZeroDate = createdatetime(1899,12,29,12,0,0)>

          <cfset myTestDate = createdatetime(2015,06,10,07,30,0)>


          <!--- Number of days = (number of hours in time period)/24 --->


          • 2. Re: convert datetime to decimal
            wannab0133 Level 1

            It turns out that the data I am using is storing days as integers(days from 12-30-1899), and times as integer(minutes from midnight i.e 0-1439).  So I am concatenating like this: days.minutes  But, I am having an issue comparing the foillowing:

            42170.720(2015-06-16 at 12:00) vs 42170.1218(2015-06-16 at 20:18)

            It is telling me the first date at noon is GT the other date.  So, I need to pad the times with zeros, so it becomes 42170.0720 instead of 42170.720.  My qoq is here:

            <cfquery name="dutyEndQuery" dbtype="query">

                    SELECT * FROM refData

                    WHERE EMPLOYEEID = '#passedEmployeeID#'

                    AND  CAST( CAST(ACTIVITYDATE as VARCHAR) + '.' + CAST(ACTIVITYTIME as VARCHAR) AS DOUBLE ) >= #passedDutyDateTime#



            Is there anyway in a qoq to pad the time portion with zeros and make the total size 4 in order to change 720 to 0720?

            • 3. Re: convert datetime to decimal
              BKBK Adobe Community Professional & MVP

              Padding with zero is not the answer. What you are actually writing as .720 and .1218 are, in fact, not decimals.


              As you yourself have suggested, the values 720 and 1218 stand for number of minutes. Thus, the time, in minutes, corresponding to the dates (2015-06-16 at 12:00) and (2015-06-16 at 20:18) are, respectively, 12x60=720 and 20x60+18=1218. You can solve the problem in 2 ways:



              Interpret the values 42170 / 720 and 42170 / 1218, respectively, as 42170+720/1439=42170.500 and 42170+1218/1439=42170.846



              Take a step back to my last post. You can determine the zero-date of your system as follows.


              You know that the date (2015-06-16 at 12:00) is equivalent to (42170 days + 720 minutes) after the zero-date. Converting everything into minutes gives (42170 x 24 x 60 + 720) minutes =  60725520 minutes. You then have

              <!--- Test date is 2015-06-16 at 12:00 --->

              <cfset myTestDate = createdatetime(2015,06,16,12,0,0)>


              <!--- Zero date is 60725520 minutes prior to test date --->

              Zero date: <cfoutput>#dateAdd("n",-60725520,myTestDate)#</cfoutput>


              This tells you that your zero date is 1899-12-30 23:00, which is equivalent to createDatetime(1899,12,30,23,0,0). You can then use this zero-date as the basis for all further date calculations.


              Suppose you wish to find any date corresponding to the format number_of_days / number_of_minutes, for example, 42170 / 1218. All you now have to do is convert everything into minutes and add to the zero date. Thus,


              <cfset zeroDate = createdatetime(1899,12,30,23,0,0)>

              <cfset newDate = dateAdd("n",42170*24*60+1218,zeroDate)>


              • 4. Re: convert datetime to decimal
                wannab0133 Level 1

                I agree that option 2 is the best option, but I need to make these calculations within SQL qoq's, where I cannot use dateadd or datediff, rather than manipulating this information within a coldfusion component.  So, I am going to utilize option 1.  Thank you for your help with this.