static string CalcDateName(DateTimeParts part, DateTime value)
{
// Attempting to match T-SQL behavior
// For any given datepart, if the values fall in the same part, then the result is zero. Then add 1 for each additional part that elapses.
// E.g. jan-12 to dec-12 is zero years difference, but dec-11 to jan-13 is two years difference, even thought the gap is only 4 months longer.
string result;
switch (part)
{
case DateTimeParts.Year:
result = value.Year.ToString();
break;
case DateTimeParts.Quarter:
result = QuarterNode.CalculateQuarter(value).ToString();
break;
case DateTimeParts.Month:
result = value.ToString("MMMM");
break;
case DateTimeParts.Day:
result = value.Day.ToString();
break;
case DateTimeParts.Week:
result = WeekNode.CalculateWeek(value).ToString();
break;
case DateTimeParts.Hour:
result = value.Hour.ToString();
break;
case DateTimeParts.Minute:
result = value.Minute.ToString();
break;
case DateTimeParts.Second:
result = value.Second.ToString();
break;
case DateTimeParts.DayOfYear:
result = value.DayOfYear.ToString();
break;
case DateTimeParts.Weekday:
result = value.ToString("dddd");
break;
default:
throw new InvalidOperationException(part.ToString());
}
return(result);
}
static int CalcDifference(DateTimeParts part, DateTime left, DateTime right)
{
// Attempting to match T-SQL behavior
// For any given datepart, if the values fall in the same part, then the result is zero. Then add 1 for each additional part that elapses.
// E.g. jan-12 to dec-12 is zero years difference, but dec-11 to jan-13 is two years difference, even thought the gap is only 4 months longer.
int result;
switch (part)
{
case DateTimeParts.Year:
result = right.Year - left.Year;
break;
case DateTimeParts.Quarter:
result = (right.Year * 12 + right.Month - 1) / 3 - (left.Year * 12 + left.Month - 1) / 3;
break;
case DateTimeParts.Month:
result = right.Year * 12 + right.Month - left.Year * 12 - left.Month;
break;
case DateTimeParts.Day:
result = (int)((right.Ticks / TimeSpan.TicksPerDay) - (left.Ticks / TimeSpan.TicksPerDay));
break;
case DateTimeParts.Week:
result = (int)((right.Ticks / TimeSpan.TicksPerDay + 1) / 7 - (left.Ticks / TimeSpan.TicksPerDay + 1) / 7);
break;
case DateTimeParts.Hour:
result = (int)((right.Ticks / TimeSpan.TicksPerHour) - (left.Ticks / TimeSpan.TicksPerHour));
break;
case DateTimeParts.Minute:
result = (int)((right.Ticks / TimeSpan.TicksPerMinute) - (left.Ticks / TimeSpan.TicksPerMinute));
break;
case DateTimeParts.Second:
result = (int)((right.Ticks / TimeSpan.TicksPerSecond) - (left.Ticks / TimeSpan.TicksPerSecond));
break;
// Because SQL just treats them the same as 'day' anyway.
case DateTimeParts.DayOfYear:
case DateTimeParts.Weekday:
default:
throw new InvalidOperationException(part.ToString());
}
return(result);
}
static DateTime AdjustDate(DateTimeParts part, int number, DateTime value)
{
DateTime result;
switch (part)
{
case DateTimeParts.Year:
result = value.AddYears(number);
break;
case DateTimeParts.Quarter:
result = value.AddMonths(number * 3);
break;
case DateTimeParts.Month:
result = value.AddMonths(number);
break;
case DateTimeParts.Day:
result = value.AddDays(number);
break;
case DateTimeParts.Week:
result = value.AddDays(number * 7);
break;
case DateTimeParts.Hour:
result = value.AddHours(number);
break;
case DateTimeParts.Minute:
result = value.AddMinutes(number);
break;
case DateTimeParts.Second:
result = value.AddSeconds(number);
break;
// Because SQL just treats them the same as 'day' anyway.
case DateTimeParts.DayOfYear:
case DateTimeParts.Weekday:
default:
throw new InvalidOperationException(part.ToString());
}
return(result);
}