尝试应用 PHP 日期格式

我正在尝试从MySql应用某种日期格式。列字段类型为"date"，在 MySQL 中格式化，例如 2015-03-16，那些没有日期的字段为 NULL。

当我应用以下代码时，带有日期的字段会正确显示 - 03/16/2015。

但是，MySQL 中的所有 NULL 字段都显示在网页中，显示 31/12/69。知道我能做什么吗？

if(!$rs = mysql_query("SELECT Vessel_Name, Builder, Built, Listing_Price, Date_Listed, LOA, Price_Original, Price_Previous, Amt_Reduced, Amt_Pct FROM boats")) {
    echo "Cannot parse query";
}
elseif(mysql_num_rows($rs) == 0) {
    echo "No records found";
}
else {
    echo "<table id='"boatstable'" class='"bordered'" cellspacing='"0'">'n";
    echo "<thead>'n<tr>";
    echo "<th>Vessel_Name</th>";
    echo "<th>Builder</th>";
    echo "<th>Built</th>";
    echo "<th>Listing Price</th>";
    echo "<th>Date Listed</th>";
    echo "<th>LOA</th>";
    echo "<th>Original Price</th>";
    echo "<th>Previous Price</th>";
    echo "<th>Amt Reduced</th>";
    echo "<th>Amt Pct</th>";
    echo "</tr>'n</thead>'n";
    while($row = mysql_fetch_array($rs)) {
        echo "<tr><td>$row[Vessel_Name]</td><td>$row[Builder]</td><td>$row[Built]</td><td>$row[Listing_Price]</td><td>".date("m/d/y", strtotime($row['Date_Listed']))."</td><td>$row[LOA]</td><td>$row[Price_Reduced]</td><td>$row[Price_Previous]</td><td>$row[Amt_Reduced]</td><td>$row[Amt_Pct]</td></tr>'n";
    }
    echo "</table><br />'n";