Hi, please try this:
xs:dateTime("2017-07-07T18:30:00.1") - xs:dayTimeDuration("PT1S") = 2017-07-07T18:30:59.1 ????? or that: xs:dateTime("2017-07-07T18:00:59.1") - xs:dayTimeDuration("PT1M") = 2017-07-07T18:00:59.1 ????? I think, there is a bug :( Best Regards Jan -- Jan Dölle E-Mail: basex-l...@id1.de Telefon +49-69-244502-0 Home: www.id1.de Information Design One AG, Baseler Straße 10, 60329 Frankfurt am Main Registereintrag: Amtsgericht Frankfurt am Main, HRB 52596 Vorstand: Robert Peters, Aufsichtsrat: Christian Hecht (Vorsitz)