When trying to pass daylight saving state change time, sub works incorrectly. $t = new DateTime( '2014-03-30 02:00:00' ); $t-add( new DateInterval('PT1H') ); echo $-format('Y-m-d H:i:s'); output will be: '2014-03-30 04:00:00'. Well, it's ok because at 3:00 a.m. Daylight saving time begins in my country, so after 02:59:59 must be 04:00:00.

But if I try to subtract time: $t = new DateTime( '2014-03-30 04:00:00' ); $t-sub( new DateInterval('PT1H') ); echo $-format('Y-m-d H:i:s'); output will be: '2014-03-30 04:00:00'. Yes, completely the same, not '2014-03-30 02:00:00' as it should be.

Subtrahieren Von Uhrzeiten

If you use diff after sub, the effects of the sub will be repeated on the date object. It doesn't matter if the object is the one diffed or doing the diffing (i.e.

Subtrahieren Von Uhrzeiten Excel

Which object you call diff from).