Php 选择查询以检查SQL数据库中的重叠日期，然后更改状态

我对PHP非常陌生，因此非常感谢您的帮助！我不确定我写的是否正确。我试着将其他论坛的不同部分拼凑起来，形成一个查询，检查数据库中是否有重叠的日期，然后将请求插入数据库，或者回显它们不可用。 我真的不确定是否对$result变量或if语句使用了正确的语法。我也在尝试使用PDO。 我知道与数据库的连接工作正常，因为当前它正在将请求插入数据库并回显消息，即使我选择了重叠的日期

我尝试了几种不同的方法来比较日期，但我似乎无法让它发挥作用，而这是最直接的方法

<?php

if(isset($_POST['request_date'])) {

  $user_id = $_SESSION['user_id'];
  $first_name = $_SESSION['first_name'];
  $last_name = $_SESSION['last_name'];
//  $request_time = date("d-m-Y H:i:s");
  $lend_status = 1;
  $lend_id = $_POST['lend_id'];
  $requested_start_date = $_POST['requested_start_date'];
  $requested_end_date = $_POST['requested_end_date'];
  $comments = $_POST['comments'];

$STH = $DBH->prepare("SELECT * FROM laptop_system WHERE approved_end_date >= requested_start_date AND requested_end_date >= approved_start_date");
$STH->execute(array());
$result = $STH->setFetchMode(PDO::FETCH_ASSOC);


if($STH->rowCount() > 0){

  echo 'sorry this date is not available';
}

else {

 $STH = $DBH->prepare("INSERT INTO laptop_system (user_id,first_name,last_name,lend_status,requested_start_date,requested_end_date,comments) VALUES(?,?,?,?,?,?,?)");
 $STH->execute(array($user_id,$first_name,$last_name,$lend_status,$requested_start_date,$requested_end_date,$comments));

  echo $first_name . ' your laptop request is now pending';

}
}

?>


<form action="" method="post" >
  <label for="requested_start_date"> Requested Start Date
  <input type="date" name="requested_start_date" value="<?php echo $requested_start_date; ?>">
  </label>
  <label for="requested_end_date">Requested End Date
  <input type="date" name="requested_end_date" value="<?php echo $requested_end_date; ?>">
  </label>
  <input type="hidden" name="lend_id" value="<?php echo $lend_id; ?>" />
  <input type="textarea" rows="4" cols="50" name="comments" placeholder="Please add any specific requirements that you might need the laptop to have and what it is beign used for. Thank you.">
  <input type="submit" name="request_date" value="Request Date">
</form>

请求的开始日期
这是因为在执行select语句后，您以错误的方式使用了select查询，因此必须在$result变量中获取结果

$STH = $DBH->prepare("SELECT * FROM laptop_system WHERE approved_end_date >= requested_start_date AND approved_start_date <= requested_end_date");
$STH->execute(); 
$result = $STH->setFetchMode(PDO::FETCH_ASSOC); // add this line after excute statement

$STH=$DBH->prepare（“从笔记本电脑系统中选择*，其中批准的结束日期>=请求的开始日期和批准的开始日期，供其他人查看同一事物的未来参考-这是一位朋友帮助我的方法

    <?php

    if (isset($_POST['request_date'])) {

        $user_id = $_SESSION['user_id'];
        $first_name = $_SESSION['first_name'];
        $last_name = $_SESSION['last_name'];
        //  $request_time = date("d-m-Y H:i:s");
        $lend_status = 1;
        $lend_id = $_POST['lend_id'];
        $requested_start_date = $_POST['requested_start_date'];
        $requested_end_date = $_POST['requested_end_date'];
        $comments = $_POST['comments'];

        // Declare available laptops array
        $available_laptops = array();

        // GET ALL LAPTOPS IN OPERATION
        $STH = $DBH->prepare("
            SELECT laptop_id,
            laptop_name
            FROM laptops
            WHERE 1
        ");
        $STH->execute(array());

        while ($row = $STH->fetch()) {

            // CHECK EACH LAPTOP FOR THE REQUESTED DATES
            $STH2 = $DBH->prepare("
                SELECT lend_id
                FROM laptop_system
                WHERE (
                    (
                        DATE(approved_start_date) <= ?
                        AND DATE(approved_end_date) > ?
                    ) OR (
                        DATE(approved_start_date) < ?
                        AND DATE(approved_end_date) >= ?
                    ) OR (
                        DATE(approved_start_date) >= ?
                        AND DATE(approved_end_date) <= ?
                    )
                )
                AND laptop_id = ?
            ");
            $STH2->execute(array(
                $requested_start_date,
                $requested_start_date,
                $requested_end_date,
                $requested_end_date,
                $requested_start_date,
                $requested_end_date,
                $row->laptop_id
            ));

            // IF IT'S NOT BOOKED OUT, ADD TO ARRAY
            if ($STH2->rowCount() < 1) {
                $available_laptops[$row->laptop_id] = $row->laptop_name;
            }

        }

        if (empty($available_laptops)) {

            echo 'Sorry, this date is not available.';

        } else {

            $STH = $DBH->prepare("
                INSERT INTO laptop_system (
                    user_id,
                    first_name,
                    last_name,
                    lend_status,
                    requested_start_date,
                    requested_end_date,
                    comments
                )
                VALUES(?, ?, ?, ?, ?, ?, ?)
            ");
            $STH->execute(array(
                $user_id,
                $first_name,
                $last_name,
                $lend_status,
                $requested_start_date,
                $requested_end_date,
                $comments
            ));

            echo $first_name . ', your laptop request is now pending approval.';

        }

    } ?>


    <form action="" method="post" >
      <label for="requested_start_date"> Requested Start Date
      <input type="date" name="requested_start_date" value="<?php echo $requested_start_date; ?>">
      </label>
      <label for="requested_end_date">Requested End Date
      <input type="date" name="requested_end_date" value="<?php echo $requested_end_date; ?>">
      </label>
      <input type="hidden" name="lend_id" value="<?php echo $lend_id; ?>" />
      <input type="textarea" rows="4" cols="50" name="comments" placeholder="Please add any specific requirements that you might need the laptop to have and what it is beign used for. Thank you.">
      <input type="submit" name="request_date" value="Request Date">
    </form>

感谢您的回复，我在中添加了一条消息，但是它现在没有提交到数据库，即使我选择了免费的日期，它也会回显“不可用”消息……您必须使用PDO计数方法更改if条件如果（$STH->rowCount（）>0），然后插入“抱歉此日期不可用”或“其他”“即使我选择了免费的日期…您在哪里选择这些日期，因为第一个查询没有参数化表单提交的任何值？如果（isset（$\u POST['request\u date']））{对于底部表单提交的select查询，应该对此进行操作-我认为….@Parfati可以在您发布的代码中看到该例程。但是，您的第一次查询没有在
select
查询中使用
？
参数化任何值，因此您如何选择免费的日期？听起来您需要使用相应的
$POST
变量在查询中参数化请求的开始日期和请求的结束日期。正如您所发现的，此查询将始终返回多行。我现在已根据下面的注释进行了更新，但仍无法确定选择时是否存在重叠日期，它仍将发布到数据库，而不是而不是回显错误消息。