Addition and subtraction arithmetic operations are supported among different interval types through support of implicit conversions. The following table defines the implicit conversion of intervals which supports the operators +, Add, - and Subtract.
| Interval | Supported Implicit Conversion Results |
|---|---|
| TdIntervalDay | TdIntervalDayToSecond, TdIntervalDayToMinute, TdIntervalDayToHour |
| TdIntervalDayToHour | TdIntervalDayToSecond, TdIntervalDayToMinute |
| TdIntervalDayToMinute | TdIntervalDayToSecond |
| TdIntervalHour | TdIntervalHourToSecond, TdIntervalHourToMinute, TdIntervalDayToSecond, TdIntervalDayToMinute |
| TdIntervalHourToMinute | TdIntervalHourToSecond, TdIntervalDayToSecond |
| TdIntervalHourToSecond | TdIntervalDayToSecond |
| TdIntervalMinute | TdIntervalHourToSecond, TdIntervalMinuteToSecond, TdIntervalHourToMinute, TdIntervalDayToSecond, TdIntervalDayToMinute |
| TdIntervalMinuteToSecond | TdIntervalHourToSecond, TdIntervalDayToSecond |
| TdIntervalSecond | TdIntervalHourToSecond, TdIntervalMinuteToSecond, TdIntervalDayToSecond |
| TdIntervalMonth | TdIntervalYearToMonth |
| TdIntervalYear | TdIntervalYearToMonth |