Date Functions
The xs:date, xs:time, and xs:dateTime data types support date and time data.
The date type xs:date represents an interval of exactly one day that begins on the first moment of a given day.
The data type xs:time represents an instant of time that recurs every day.
The data type xs:dateTime represents an instant in time.
The data type xs:duration represents a duration of time that is expressed by the Gregorian year, month, day, hour, minute, and second components. xs:duration is derived from data type xs:anyAtomicType.
The data type xs:dayTimeDuration represents a duration of time that is expressed by days, hours, minutes, and seconds components. xs:dayTimeDuration is derived from data type xs:duration.
The data type xs:yearMonthDuration represents a duration of time that is expressed by the Gregorian year and month components. xs:yearMonthDuration is derived from data type xs:duration.
https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzasp/rzasp_xsdatetimetype.htm