WordPress博客内容字符限制

Stack的伟大人物，我再次需要您的帮助。

我目前有一个外部网站，它从包含WordPress安装的子文件夹中提取博客内容，例如：

网站A：外部静态网站网站B:WordPress安装

我使用以下代码在网站A的主页上发布了帖子。

WordPress呼叫：

<?php  
//db parameters  
$db_username = '###';  
$db_password = '###';  
$db_database = '###';  
$blog_url = 'http://www.website.com/blog/';
//connect to the database  
mysql_connect('###', $db_username, $db_password);  
@mysql_select_db($db_database) or die("Unable to select database");  
//get data from database -- !IMPORTANT, the "LIMIT 5" means how many posts will appear. Change the 5 to any whole number.  
$query = "Select * FROM wp_posts WHERE post_type='post' AND post_status='publish' ORDER BY id DESC LIMIT 1";   
$query_result = mysql_query($query);  
$num_rows = mysql_numrows($query_result);  
//close database connection  
mysql_close();  
// html page starts after 
?>  

博客文章包含：

<div class="contentBox">
    <?php  
    for($i=0; $i< $num_rows; $i++){   
   //assign data to variables, $i is the row number, which increases with each run of the loop  
   $blog_date = mysql_result($query_result, $i, "post_date");  
   $blog_title = mysql_result($query_result, $i, "post_title");  
   $blog_content = mysql_result($query_result, $i, "post_content");  
   //$blog_permalink = mysql_result($query_result, $i, "guid"); //use this line for p=11 format.  
   $blog_permalink = $blog_url . mysql_result($query_result, $i, "post_name"); //combine blog url, with permalink title. Use this for title format  
                        //format date  
                        $blog_date = strtotime($blog_date);  
                        $blog_date = strftime("%b %e", $blog_date);  
                        //the following HTML content will be generated on the page as many times as the loop runs. In this case 5.  
                        ?>
                        <div class="post"></div>  
                        <img src="img/headers/news-from.png" /><br />
                                <p class="blogName"><a href="http://www.website.com/blog"><?php echo $blog_title; ?></a></p>  
                                <p style="margin-top: -10px; margin-right: 10px;"><?php echo $blog_content;?></p>  
                                <p>Submitted on: <span class="green"><?php echo $blog_date; ?></span></p>   
                                <p><a href=”<?php echo $blog_permalink; ?>”>Read Full Post</a></p>  
                        <?php  
                            } //end the for loop  
                        ?>
                    </div>

这工作得很好，它提取了必要的帖子并显示出来，格式都很好等等。我的问题是，我真的需要限制提取的字符数，目前，这是整个帖子的回声，我只需要回声帖子的前15个字符。任何想法都将不胜感激。