WP_Query min and max values
Depending on the way your script is recording max_price, it isn’t really a meta_key/meta_value on postmeta table. Did you try changin max_price clause to something like this? [‘max_price’] => [ ‘relation’ => ‘OR’, [ ‘key’ => ‘max_price’, ‘value’ => 11, ‘compare’ => ‘<=’, ], [ ‘key’ => ‘max_price’, ‘compare’ => ‘NOT EXISTS’, ], ],