The DateDifference( date1, date2 ) command computes the time between the dates represented by two Date objects date1 and date2.

By default, the difference of the two dates is returned using the units of the system UTC clock. This is the same result computed by the expression date2 - date1. However, you can express the time difference between date1 and date2 in other units by using the units = u option with either a valid unit symbol u (e.g., days), or the special name mixed.

$\mathrm{with}\left(\mathrm{Calendar}\right)\:$

$\mathrm{d1}≔\mathrm{Date}\left(2016\,3\,4\,2\,2\,0\,'\mathrm{timezone}'=''America/Caracas''\right)$

$\mathrm{d1}≔\mathrm{<Date:\; 2016-03-04T02:02:00\; Venezuela\; Time>}$

$\mathrm{d2}≔\mathrm{Date}\left(1997\&comma;1\&comma;1\&comma;0\&comma;'\mathrm{timezone}'=''Asia/Hong\_Kong''\right)$

$\mathrm{d2}≔\mathrm{<Date:\; 1997-01-01\; Hong\; Kong\; Standard\; Time>}$

$\mathrm{DateDifference}\left(\mathrm{d2}\&comma;\mathrm{d1}\right)$

$605025120000⟦\mathrm{ms}⟧$

$\mathrm{DateDifference}\left(\mathrm{d2}\&comma;\mathrm{d1}\&comma;'\mathrm{units}'='\mathrm{days}'\right)$

$\frac{1260469}{180}⟦d⟧$

$\mathrm{DateDifference}\left(\mathrm{d2}\&comma;\mathrm{d1}\&comma;'\mathrm{units}'='\mathrm{hours}'\right)$

$\frac{2520938}{15}⟦h⟧$

$\mathrm{DateDifference}\left(\mathrm{d2}\&comma;\mathrm{d1}\&comma;'\mathrm{units}'='\mathrm{mixed}'\right)$

$19⟦{\mathrm{yr}}_{\mathrm{standard}}⟧+2⟦\mathrm{mo}⟧+8⟦d⟧+13⟦h⟧+3⟦\min ⟧+54⟦s⟧+400⟦\mathrm{ms}⟧$

$\mathrm{BattleOfMarathon}≔\mathrm{Date}\left(-489\&comma;9\&comma;12\right)$

$\mathrm{BattleOfMarathon}≔\mathrm{<Date:\; 0490-09-12T12:00:00\; GMT>}$

$\mathrm{BattleOfThermopylae}≔\mathrm{Date}\left(-479\&comma;8\&comma;20\right)$

$\mathrm{BattleOfThermopylae}≔\mathrm{<Date:\; 0480-08-20T12:00:00\; GMT>}$

$\mathrm{DateDifference}\left(\mathrm{BattleOfMarathon}\&comma;\mathrm{BattleOfThermopylae}\&comma;'\mathrm{units}'='\mathrm{mixed}'\right)$

$9⟦{\mathrm{yr}}_{\mathrm{standard}}⟧+11⟦\mathrm{mo}⟧+20⟦d⟧+3⟦h⟧+55⟦\min ⟧+29⟦s⟧+200⟦\mathrm{ms}⟧$

The Calendar[DateDifference] command was introduced in Maple 2018.

For more information on Maple 2018 changes, see Updates in Maple 2018.