Returns the xs:dayTimeDuration that corresponds to the elapsed time between
the starting instant of $arg2 and the starting instant of
$arg2.
xs:date values.op:subtract-dates( $arg1 as xs:date,$arg2 as xs:datexs:dayTimeDurationIf either $arg1 or $arg2 do not contain an explicit timezone
then, for the purpose of the operation, the implicit timezone provided by the dynamic
context (See .) is
assumed to be present as part of the value.
The starting instant of an xs:date is the xs:dateTime at
00:00:00 on that date.
The function returns the result of subtracting the two starting instants using
op:subtract-dateTimes.
If the starting instant of $arg1 precedes in time the starting instant of
$arg2, then the returned value is a negative duration.
Assume that the dynamic context provides an implicit timezone value of
Z.
The expression op:subtract-dates(xs:date("2000-10-30"),
xs:date("1999-11-28")) returns xs:dayTimeDuration("P337D").
Now assume that the dynamic context provides an implicit timezone value of
+05:00.
The expression op:subtract-dates(xs:date("2000-10-30"),
xs:date("1999-11-28Z")) returns xs:dayTimeDuration("P336DT19H").
The expression op:subtract-dates(xs:date("2000-10-15-05:00"),
xs:date("2000-10-10+02:00")) returns xs:dayTimeDuration("P5DT7H").
