This expression will extract the date from the field in format YYYYMMDD and it will be converted to integer
i.e. '2017-01-03 13:18:13.667' --> 20170103 (int) Just replace for your field name
(DT_I4)((DT_WSTR,4)(DATEPART("yyyy", <datetime>)) +
RIGHT("0" + (DT_WSTR,2)DATEPART("mm", <datetime>), 2) +
RIGHT("0" + (DT_WSTR,2)DATEPART("dd", <datetime>), 2))