How do I structure a sql that: 2 checks if meta_value is in future or has no meta_value at all and 1 orders by meta_value (meta_key => datum_event), and conditionally if this meta_value is empty uses postdate to order.
The ordering of the query should be handled like one block (not two ordered sections).
This is a two step issue 1 query 2 orderby.
Currently this is my sql (not working):
Only if I remove the complete 'meta_query' => array posts with no content for datum_event are shown, the first inner array does work to query posts from the past (compare' => '<=').
$args = array(
'post_type' => array(
'nieuws',
'blog',
'agenda'
),
'meta_query' => array(
'relation' => 'OR',
// if has content for datum_event:
array(
'key' => 'datum_event',
'value' => date('Ymd'),
'compare' => '<=',
// use datum_event to orderby:
'meta_key' => 'datum_event',
'meta_type' => 'DATE',
'orderby' => 'meta_value',
'order' => 'ASC',
),
// if has no content for datum_event:
array(
'key' => 'datum_event',
'meta_compare' => 'NOT_EXISTS',
// order by date:
'orderby' => 'date',
),
),
);