我有三张table
tbl\新闻\文章

1   newsIDPrimary   int(4)
2   type    int(3)  
3   title   varchar(40) 
4   body    medium text
5   date    date

tbl\U图像

1   imageIDPrimary  int(4)
2   filename   varchar(40)

tbl\新闻\图片

1   newsIDIndex int(4)
2   imageIDIndex    int(4)

所以tbl\u news\u article保存文章数据，tbl\u images保存图像数据，tbl\u new\u images保存文章的id和图像的id。
每个新闻文章通常会有一个图像，但可以有多个图像，但有时没有一个特定的新闻文章的图像。
当一篇文章没有图片时，问题就一直存在。
我的问题是

$sql = "SELECT n.newsID, n.type, n.title, n.body, n.date, ni.newsID, ni.imageID, i.imageID, i.filename FROM tbl_news_articles AS n 
            LEFT JOIN tbl_news_images AS ni ON ni.newsID = n.newsID 
            LEFT JOIN tbl_images AS i ON i.imageID = ni.imageID 
            ORDER BY date DESC

返回以下记录

newsID -> 61
type -> 0
title -> title 1
body -> article body text
date -> 2016-10-01
newsID -> NULL
imageID -> NULL
imageID -> NULL
filename -> NULL

newsID -> 62
type -> 0
title -> title 2
body -> article body text
date -> 2016-10-01
newsID -> 62
imageID -> 2
imageID -> 2
filename -> group.jpg

在我的网站上，我会显示每篇文章的一个片段，其中有一个指向全文的链接，问题是当试图在数据库中没有链接到它的图像的文章上单击全文链接时，newsid行返回null而不是实际的newsid值。
我的php代码是

<?php
        //call the database to retreive the records
        $sql = "SELECT n.newsID, n.type, n.title, n.body, n.date, ni.newsID, ni.imageID, i.imageID, i.filename FROM tbl_news_articles AS n 
        LEFT JOIN tbl_news_images AS ni ON ni.newsID = n.newsID 
        LEFT JOIN tbl_images AS i ON i.imageID = ni.imageID 
        ORDER BY date DESC LIMIT $offset, $rowsperpage";
        $result = $conn->query($sql);
        $i = 0;
        if ($result->num_rows > 0)
        {
            // output data of each row
            while($row = $result->fetch_assoc())
            {
                $id = $row['newsID'];
                $link = "article.php?id=".$id;
                $type = $row['type'];
                $title = $row['title'];
                $urltitle = strtolower($title);
                $urltitle = str_replace(" ","-",$urltitle);
                $body = $row['body'];
                #$bodytext = (strlen($body) > 130) ? substr($body,0,130).'...' : $bodytext;
                $pos= strpos($body, ' ', 140);
                $bodytext = substr($body,0,$pos); 
                $bodytext .= "... <a href='$link' title='$title'>read more</a>";
                $date = $row['date'];
                $formated_date = date("d-M-Y", strtotime($date));
                $imgID = $row['imageID'];
                $filename = $row['filename'];
                if($filename != "")
                {
                    $imgLink = "images/news-articles/".$id."/".$filename;
                }
                else
                {
                    $imgLink = "images/news-item-placeholder.jpg";
                }
                $i++;
                if($i == 1)
                {
                    echo "<div class='news-spotlight'>";
                }
                elseif($i >=2 && $i <=3)
                {
                    if($i == "2")
                    {
                        $class = "first";
                    }
                    else
                    {
                        $class = "";
                    }
                    echo "<div class='news-highlight $class'>";
                }
                else
                {
                    echo "<div class='news-item'>";
                }?>
                <a itemprop="url" href="<?php echo $link?>"><img itemprop="image" src="<?php echo $imgLink?>" alt="<?php echo $title?>" title="<?php echo $title?>"></a>
                <div class='data'>

                <h3><a href="<?php echo $link?>"><span itemprop="name"><?php echo $title?></span></a></h3>
                <div class="article-date"><?php echo $formated_date?></div>
                <span itemprop="startDate" content="<?php echo $date?>"></span>
                <div itemprop="location" itemscope itemtype="http://schema.org/Place">          
                <span itemprop="address" content="England"></span>
                <span itemprop="name" content="MayoShinDo Association"></span>
                </div>
            <p itemprop="description"><?php echo $bodytext?></p>

            <?php if($i == 1)
            {?>
            <ul>
                <li><a href="<?php echo $link?>"><span class="glyphicon glyphicon-ok" aria-hidden="true"></span> link 1</a></li>
                <li><a href="<?php echo $link?>"><span class="glyphicon glyphicon-ok" aria-hidden="true"></span> link 2</a></li>
                <li><a href="<?php echo $link?>"><span class="glyphicon glyphicon-ok" aria-hidden="true"></span> link 3</a></li>
                <li><a href="<?php echo $link?>"><span class="glyphicon glyphicon-ok" aria-hidden="true"></span> link 4</a></li>
            </ul><?php
            }?>
            </div><?php
                echo "</div>";
            }
        }
        else
        {
            echo "0 Results";   
        }?>

我确定问题出在连接上，但我尝试过使用内部连接和外部连接，但都没有返回预期的数据。
我甚至试过用下面的

$id = $row['n.newsID'];

以特定的newsid字段为目标，但这又进一步打破了局面，有人能帮忙吗？
谢谢