__int64 __fastcall
      SubtractDateFromDateAsDayTime(System::TDateTime FirstValue,
      System::TDateTime SecondValue, TEDBDayTimeIntervalType
      DayTimeIntervalType)

 In ElevateDB, day-time intervals are Int64 values that represent the number of milliseconds that have elapsed between two points in time. Use the TEDBEngine DayTimeIntervalToSQLStr method to convert a day-time interval into a readable string.