如果数组元素在2个日期之间，则返回文本PHP

我有以下PHP代码，我打算用它创建一封HTML电子邮件，它应该输出所有模型的详细信息，到期日在2个设定日期之间：

$sql = 'SELECT
GROUP_CONCAT(op.products_model),
GROUP_CONCAT(products.products_warranty_default),
GROUP_CONCAT(orders.date_purchased),
orders.customers_name
FROM orders_products op
INNER JOIN products
    ON op.products_id = products.products_id
INNER JOIN orders
    ON op.orders_id = orders.orders_id
INNER JOIN customers
    ON orders.customers_id = customers.customers_id
GROUP BY op.orders_id';
$result = mysql_query($sql, $connection);
while ($data = mysql_fetch_row($result)) {
    $models = explode(",",$data[0]); // create array from all models in the GROUP_CONCAT
    $years = explode(",",$data[1]); // create array from all years in the GROUP_CONCAT
    $dates = explode(",",$data[2]); // create array from all dates in the GROUP_CONCAT
    $name = $data[3];
    echo $header; // header of email (only the name changes on each loop)
    foreach ($models as $index => $model) {
    echo '
    <tr>
        <td width="149">
            <center>'.$model.'</center>
        </td>
        <td width="149">
            <center>'.date('d/m/Y', strtotime('+'.$years[$index].' years', strtotime($dates[$index]))).'</center>
        </td>
    </tr>'; // echos the model in first column and date+years in second column
    }
    echo $footer; // static HTML again like the header
}

我一直在思考的是，如果表中存在日期在两个日期之间的模型，即2014年5月1日至5月31日，如何仅输出页眉、表和页脚的组合。它当前正在输出所有日期。

我试过各种方法来做到这一点，但在大约6个小时的失败后，我准备把我的电脑扔出窗外。我只有几周的PHP经验（以及编程经验），所以它可能（希望）是一个我不知道的简单修复。

注意：我应该注意的是，对于我用来测试的当前数据库，我可以修改选择查询以输出相关日期，但在我使用的实际数据库（我只能在工作中访问该数据库）上没有保修字段，我必须通过php从产品的长描述中提取信息，并将其输入到一个函数中。

最终代码：

$sql = 'SELECT  op.products_model, 
        products.products_warranty_default,
        orders.date_purchased,
        orders.customers_name
   FROM orders_products op
  INNER JOIN products  ON op.products_id = products.products_id
  INNER JOIN orders    ON op.orders_id = orders.orders_id
  INNER JOIN customers ON orders.customers_id = customers.customers_id
  ORDER BY orders.customers_name, op.orders_id,
           op.products_model,
           products.products_warranty_default,
           orders.date_purchased';
$result = mysql_query($sql, $connection);
$previous_name = "";
while ($data = mysql_fetch_row($result)) {
    $model = $data[0];
    $year = $data[1];
    $date = $data[2];
    $name = $data[3];
    $expiry = strtotime('+'.$year.' years', strtotime($date));
    if ($previous_name != $name && $expiry >= strtotime('2014-05-01') && $expiry <= strtotime('2014-05-31')) {  // on a new customer name ...
        if ($previous_name != "") {
            // if there is a previous customer, write the footer
            echo $footer;
            $previous_name = $name; 
        }
    }
    if ($expiry >= strtotime('2014-05-01') && $expiry <= strtotime('2014-05-31')){
    echo '
    <tr>
        <td width="149">
                <center>'.$model.'</center>
        </td>
        <td width="149">
            <center>'.date('d/m/Y', $expiry).'</center>
        </td>
    </tr>'; // echos the model in first column and date+years in second column
    }
}
if ( $previous_name != "" && $expiry >= strtotime('2014-05-01') && $expiry <= strtotime('2014-05-31')) {
    echo $footer;
}