代码实现本篇文章的前几篇和后几篇功能

wenchenhk_get_post.php

<? php
//前几篇后几篇文章
function wenchenhk_get_post( $previous = true, $number = 1 ) {  
    
    //global当前文章变量 $post 和数据库操作类wpdb  
    global $post, $wpdb;  
    if ( empty( $post ) )  
        return null;  
    
    $current_post_date = $post->post_date;//当前文章的时间  
    
    $join = '';  
    $posts_in_ex_cats_sql = '';  
    //加入表  
    $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";  
    //获取当前文章所属分类,可以同属多个分类,如果是自定义的分类法,将category换成对应的分类法即可  
    $cat_array = wp_get_object_terms($post->ID, 'category', array('fields' => 'ids'));  
    $join .= " AND tt.taxonomy = 'category' AND tt.term_id IN (" . implode(',', $cat_array) . ")";  
    
    //判断时间是大于还是小于  
    $op = $previous ? '<' : '>';  
    //排序  
    $order = $previous ? 'DESC' : 'ASC';  
         
    $where = $wpdb->prepare("WHERE p.post_date $op %s AND p.post_type = %s AND p.post_status = 'publish' ", $current_post_date, $post->post_type);  
    $sort  = "ORDER BY p.post_date $order LIMIT 0, $number";  
    
    $query = "SELECT p.* FROM $wpdb->posts AS p $join $where $sort";  
    $query_key = 'adjacent_post_' . md5($query);  
    $result = wp_cache_get($query_key, 'counts');  
    if ( false !== $result )  
        return $result;  
    
    $result = $wpdb->get_results("SELECT p.* FROM $wpdb->posts AS p $join $where $sort");  
    if ( null === $result )  
        $result = '';  
    wp_cache_set($query_key, $result, 'counts');  
    return $result;  
}
?>