Update the result of an inner join from a SQL table

UPDATE @result
SET selectiondate=eventdatetime
FROM @result r
INNER JOIN (
  SELECT r.id, MAX(h.EventDateTime) eventdatetime
  FROM @result r
  LEFT JOIN statehistory h WITH (NOLOCK) ON h.id = r.id AND h.eventid = @CONST_SelectedEvent
  GROUP BY r.id
) d ON d.id=r.id