echo "<hr>Last SQL-Query: {$the_query->request}";

SELECT SQL_CALC_FOUND_ROWS wp_posts.ID FROM wp_posts INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id ) WHERE 1=1 AND ( wp_postmeta.meta_key = 'client' ) AND wp_posts.post_type = 'post' AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') GROUP BY wp_posts.ID ORDER BY wp_postmeta.meta_value DESC LIMIT 0, 2

$the_query = new  WP_Query
         (
                  array
                  (
                        'meta_key'=> 'client',
                        'orderby' => 'meta_value',
                        'order'   => 'DESC'
                  )
        );

echo "<hr>Last SQL-Query: {$the_query->request}";