In my args I would like to exclude posts where the datum_event is not in the future. Currently it only displays posts with datum_event values that are in the past, but because older posts don't have any value for datum_event, the old posts don't get shown.
I know how to compare against a single value, but how do I compare against all future dates?
Basically: EXCLUDE posts with
$args = array( 'post_type' => 'agenda', 'paged' => $paged, 'meta_query' => array( array( 'key' => 'datum_event', 'value' => date('Ymd'), 'compare' => '<=' ) ), );