Get several adjacent posts in one query
There are number of functions in WordPress to get one of the adjacent (neighboring) posts to the current one: get_previous_post() and get_next_post().
But they can only get one post. And what to do when you need to get several adjacent (bordering, edge) posts that are close to the current one (around - before and after it).
1 2 3 4 - current post 5 6 7
The problem can be solved with two queries using WP_Query, but let's do it with one query!
/** * Gets adjacent posts (by date). * * @param array $args { * Array of arguments. * * @type int $limit By how many neighboring records you need to get. * @type bool $in_same_term Get posts only from the same terms in which the current post is. * @type string $taxonomy Tax name. When $in_same_term = true, WP need to know which tax to work with. * @type int/WP_Post $post Post adjacent posts of which to get. Default: current post. * @type string $order Sort order. If DESC - 'prev' element will contain new posts and 'next' olds one. If ASC Vice-versa... * @type bool $cache_result Is it need to cache the result to object cache? * } * * @return array Array like: array( 'prev'=>array(posts), 'next'=>array(posts) ) or array() if the records could not be retrieved or there is an error in the request. * * @ver 1.0 */ function get_post_adjacents( $args = array() ) { global $wpdb; $args = (object) array_merge( array( 'limit' => 3, 'in_same_term' => false, 'taxonomy' => 'category', 'post' => $GLOBALS['post'], 'order' => 'DESC', 'cache_result' => false, ), $args ); $post = is_numeric($args->post) ? get_post($args->post) : $args->post; // in_same_term $join = $where = ''; if ( $args->in_same_term ) { $join .= " INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id"; $where .= $wpdb->prepare( "AND tt.taxonomy = %s", $args->taxonomy ); if ( ! is_object_in_taxonomy( $post->post_type, $args->taxonomy ) ) return array(); $term_array = wp_get_object_terms( $post->ID, $args->taxonomy, ['fields'=>'ids'] ); // Remove any exclusions from the term array to include. //$term_array = array_diff( $term_array, (array) $excluded_terms ); if ( ! $term_array || is_wp_error( $term_array ) ) return array(); $term_array = array_map( 'intval', $term_array ); $where .= " AND tt.term_id IN (" . implode( ',', $term_array ) . ")"; } $query = " ( SELECT p.* FROM $wpdb->posts p $join WHERE p.post_date > '". esc_sql($post->post_date). "' AND p.post_type = '". esc_sql($post->post_type). "' AND p.post_status = 'publish' $where ORDER BY p.post_date ASC LIMIT ". intval($args->limit) ." ) UNION ( SELECT * FROM $wpdb->posts WHERE ID = $post->ID ) UNION ( SELECT p.* FROM $wpdb->posts p $join WHERE p.post_date < '". esc_sql($post->post_date) ."' AND p.post_type = '". esc_sql($post->post_type) ."' AND p.post_status = 'publish' $where ORDER BY p.post_date DESC LIMIT ". intval($args->limit) ." ) ORDER by post_date ".( $args->order === 'DESC' ? 'DESC' : 'ASC' )." "; // try to get cache if( $args->cache_result ){ $query_key = 'post_adjacents_' . md5( $query ); $result = wp_cache_get( $query_key, 'counts' ); if( false === $result ) $result = $wpdb->get_results( $query, OBJECT_K ); // cache result if( ! $result ) $result = array(); wp_cache_set( $query_key, $result, 'counts' ); } else $result = $wpdb->get_results( $query, OBJECT_K ); // collect prev/next arrays if( $result ){ $adjacents = array( 'prev'=>[], 'next'=>[] ); $indx = 'prev'; foreach( $result as $pst ){ //unset($pst->post_content); // for debug // current post if( $pst->ID == $post->ID ){ $indx = 'next'; continue; } $adjacents[ $indx ][ $pst->ID ] = get_post( $pst ); // create WP_Post objects } } // debug //$posts_tits = wp_list_pluck( $result, 'post_title' ); //die( print_r( $posts_tits ) ); return $adjacents; }
Example of usage
$adjacents = get_post_adjacents([ 'post' => 10253 ]); print_r( $adjacents );
Get:
Array( [prev] => Array ( [10415] => WP_Post Object [ID] => 10415 [post_author] => 141 [post_date] => 2018-07-14 17:23:56 [post_date_gmt] => 2018-07-14 12:23:56 [post_title] => Post Title 1 ... [10339] => WP_Post Object [ID] => 10339 [post_author] => 141 [post_date] => 2018-06-19 00:40:03 [post_date_gmt] => 2018-06-18 19:40:03 [post_title] => Post Title 2 ... [10276] => WP_Post Object [ID] => 10276 [post_author] => 141 [post_date] => 2018-06-14 23:35:17 [post_date_gmt] => 2018-06-14 18:35:17 [post_title] => Post Title 3 ... ) [next] => Array ( [10040] => WP_Post Object [ID] => 10040 [post_author] => 1 [post_date] => 2018-05-21 21:35:48 [post_date_gmt] => 2018-05-21 16:35:48 [post_title] => Post Title 5 ... [10097] => WP_Post Object [ID] => 10097 [post_author] => 1 [post_date] => 2018-05-21 13:13:21 [post_date_gmt] => 2018-05-21 08:13:21 [post_title] => Post Title 6 ... [10084] => WP_Post Object [ID] => 10084 [post_author] => 1 [post_date] => 2018-05-17 13:53:47 [post_date_gmt] => 2018-05-17 08:53:47 [post_title] => Post Title 7 ... ) )