当我们的WordPress博客历史越来越悠久后，我们就会发现，在N年前的今天，我们也曾经发表了某某文章。而今天就来教大家如何于WordPress文章内添加上“历史上的今天”功能，让站长和访客一同体会网站历史

在模板的function.php最下面，也就是“?>”之前添加下面代码即可实现：

function wp_history_post_base($post_year, $post_month, $post_day){
	global $wpdb;
	$limit = 30;
	$order = "latest";
	if($order == "latest"){ $order = "DESC";} else { $order = '';}
	$sql = "select ID, year(post_date_gmt) as h_year, post_title, comment_count FROM 
	$wpdb->posts WHERE post_password = '' AND post_type = 'post' AND post_status = 'publish'
	AND year(post_date_gmt)!='$post_year' AND month(post_date_gmt)='$post_month' AND day(post_date_gmt)='$post_day'
	order by post_date_gmt $order limit $limit";
	$histtory_post = $wpdb->get_results($sql);
	return $histtory_post;
}
 
function wp_history_post_single(){
	$wp_history_post_content_list = '
%YEAR%年：%TITLE%（%COMMENTS_NUM%条评论）
';
	$wp_history_post_content_title = '
历史上的今天
';
	$histtory_post = wp_history_post_base(get_the_time('Y'), get_the_time('m'), get_the_time('j'));
	if($histtory_post){
		foreach( $histtory_post as $post ){
			$h_year = $post->h_year;
			$h_post_title = $post->post_title;
			$h_permalink = get_permalink( $post->ID );
			$h_comments = $post->comment_count;
			$h_post .= $wp_history_post_content_list;
			$h_post = str_replace("%YEAR%", $h_year, $h_post);
			$h_post = str_replace("%LINK%", $h_permalink, $h_post);
			$h_post = str_replace("%TITLE%", $h_post_title, $h_post);
			$h_post = str_replace("%COMMENTS_NUM%", $h_comments, $h_post);
		}
	}
	if($h_post){
		$result = $wp_history_post_content_title.$h_post;
	}
	return $result;
	wp_reset_query();
}
 
function wp_history_post_content($content){
	global $wpdb;
	if(is_single()){
		$content .= wp_history_post_single();
	}
	return $content;
}
add_action('the_content', 'wp_history_post_content');

刷新所有的缓存，即可实现，赶紧试试吧