wordpress $query->set by meta key value - wordpress

Question

I am trying to modify all queries of a post type "products" to only show if the product/post has a certain meta_key of "wholesale_price" which the meta_value needs to be greater than 0.
Here is what i have:
add_action( 'pre_get_posts', 'rc_modify_query_get_design_projects' );
function rc_modify_query_get_design_projects( $query ) {
if($query->is_main_query() && $query->query_vars['post_type'] == 'product' ) {
$query->set('meta_key', 'wholesale_price');
$query->set('meta_compare', '>');
$query->set('meta_value', '0');
}
}
For some reason this still returns everything. Is this the right way of doing things?

Answer 1

The problem is the method by which you are setting your meta_query. You should read up on the WP_Query functionality, because meta queries are unfortunately not that simple.
You need to do something more like so:
add_action( 'pre_get_posts', 'rc_modify_query_get_design_projects' );
function rc_modify_query_get_design_projects( $query ) {
// Do not add meta arguments in admin pages
if (is_admin()) {
return;
}
if($query->is_main_query() && $query->query_vars['post_type'] == 'product' ) {
//Get original meta query
$meta_query = (array)$query->get('meta_query');
// Add your criteria
$meta_query[] = array(
'key' => 'wholesale_price',
'value' => 0,
'compare' => '>',
);
// Set the meta query to the complete, altered query
$query->set('meta_query',$meta_query);
}
And no need to return anything in this function.