meta_query compare=’!=’ with multiple custom fields

by

This might require writing custom sql with a subquery:

$results = $wpdb->get_results("
    SELECT * 
    FROM $wpdb->posts 
    WHERE ID NOT IN (
      SELECT post_id FROM $wpdb->postmeta
      WHERE meta_key = 'my_custom_field' and meta_value = 2
    )
");

then just iterate through the results as described here.