How to format the output of the DATETIME_DIFF formula

Formulas
1

I’m trying to calculate the difference between two “Date Time” fields as a time using the formula “DATETIME_DIFF({Arrival Time}, {Departure Time})”.
When I format the field as “Time”, the result is always 1:00 or 1:02. There is no option to select a “Date time” field as the output.
If I leave the field as “Decimal” by default, it outputs the number of seconds (which is mathematically correct).
How can I format the formula so that the difference is displayed as DD:MM:SS?

Thanks & regards,
Ulrich

2

You can use below formula

CONCAT(FLOOR((DATETIME_DIFF({End}, {Start}, "seconds") / 86400)), ":", FLOOR((MOD(DATETIME_DIFF({End}, {Start}, "seconds"), 86400) / 3600)), ":", FLOOR((MOD(DATETIME_DIFF({End}, {Start}, "seconds"), 3600) / 60)), ":", MOD(DATETIME_DIFF({End}, {Start}, "seconds"), 60))

and if you prefer zero padded output

CONCAT(
    RIGHT(CONCAT('00', FLOOR(DATETIME_DIFF({End}, {Start}, 'seconds') / 86400)), 2), ':',
    RIGHT(CONCAT('00', FLOOR(MOD(DATETIME_DIFF({End}, {Start}, 'seconds'), 86400) / 3600)), 2), ':',
    RIGHT(CONCAT('00', FLOOR(MOD(DATETIME_DIFF({End}, {Start}, 'seconds'), 3600) / 60)), 2), ':',
    RIGHT(CONCAT('00', MOD(DATETIME_DIFF({End}, {Start}, 'seconds'), 60)), 2)
  )