meta_query 'compare' => '!=' not working

Question

I am using a custom post-type, in post there are a checkbox meta field for featured post.

So there are two scenarios.

1. First with featured posts
2. Second with non featured

When I called featured posts with meta_query its result 100% perfect.

Here is my code:

$c_clients_args = array(
                    'post_type' => 'clients_testimonials',
                    'posts_per_page' => 6,
                    'order' => 'ASC',
                    'meta_query' => array(
                                        array(
                                            'key' => 'c_client_feature',
                                            'value' => 'on'
                                        )
                                    )
                );

$c_clients_result = new WP_Query($c_clients_args);

if($c_clients_result->have_posts()) :
    while($c_clients_result->have_posts()) :
         $c_clients_result->the_post();

         // My result
    endwhile;
endif;

But when I call non featured posts with meta_query the Page goes blank.

Here is my code:

$c_client_args = array(
                    'post_type' => 'clients_testimonials',
                    'posts_per_page' => 999,
                    'order' => 'ASC',
                    'meta_query' => array(
                                        array(
                                            'key' => 'c_client_feature',
                                            'value' => 'on',
                                            'compare' => 'NOT LIKE'
                                        )
                                    )
                );

I also tried != and NOT IN

So please guide me.

Answer 1

try this second query

  $c_client_args = array(
                    'post_type' => 'clients_testimonials',
                    'posts_per_page' => 999,
                    'order' => 'ASC',
                    'meta_query'  => array(
                         'relation' => 'OR',
                          array(
                             'key' => 'c_client_feature',
                             'compare' => 'NOT EXISTS' 
                          ),
                          array(
                             'key' => 'c_client_feature',
                             'value' => 'on',
                             'compare' => 'NOT IN' 
                          ),
                        )
                );