I've got a custom area title "front_sl_slider". I wish to display all of the posts which have custom area "front_sl_slider" value set to at least one. also, i wish to display, thumbnail, title, along with other custom fields data for that posts which i get as a consequence of my query.

$meta_pages = $wpdb->get_results("SELECT *    FROM $wpdb->posts WHERE  post_type = 'page' AND  meta_key = 'front_sl_slider' AND meta_value = 1 ORDER BY menu_order", 'OBJECT'); 
    if ( $meta_pages ) 
        {
        foreach ( $meta_pages as $pageChild1 ) : setup_postdata( $pageChild1 );
         echo get_post_meta($pageChild1->ID, 'front_sl_slider', true);
         echo get_post_meta($pageChild1->ID, 'project_client_name', true) ."<br>";
         echo get_post_meta($pageChild1->ID, 'project_architect', true) ."<br>"; 
        endforeach; 
        }
$querystr = "   SELECT $wpdb->posts.* , $wpdb->postmeta.*
                        FROM $wpdb->posts, $wpdb->postmeta
                        WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id 
                        AND $wpdb->postmeta.meta_key = 'Featured_Projects_Page' 
                        AND $wpdb->postmeta.meta_value = 1 
                        AND $wpdb->posts.post_type = 'page'
                        ORDER BY $wpdb->posts.post_date DESC
                     ";
$pageposts = $wpdb->get_results($querystr, OBJECT);

do this, this will work.