Question

我的数据库中有2个关系表。

我一直想把头转到下面。

我有联系表，我有一张订单表。

我想尝试显示联系信息（姓名，电子邮件等）一次，然后显示订单信息。

我知道我可以这样做：

<?php 
  $query = $db->prepare("SELECT *
                     FROM contact 
             WHERE type = ? 
             ORDER BY date") 
             or die(mysqli_error($db));  
  $type = "order";
  $query->bind_param('s', $type);
  $query->execute(); 
  $query->store_result(); 
  $query->bind_result($id, $name, $email, $date); 

  while ($query->fetch()) {
     $date = strtotime($date); 
     $date = date("F jS  Y", $date);
?>


From: <?php echo $name ?>

<input type="Checkbox" name="checkbox[]"  id="checkbox[]"value="<? echo $contactid; ?>">

<p>
<?php 
   echo $comments 
?>
</p>

<?php 
     echo $date ;
?>

<?php
     $order = $db->prepare("SELECT title, number
             FROM preorder 
             WHERE id = ? ") 
             or die(mysqli_error($db));  

     $order->bind_param('s', $id);
     $order->execute(); 
     $order->store_result(); 
     $order->bind_result( $title, $number ); 

     while ($order->fetch()) {
        echo $title, $number ; 
     }  
   } 
?>

这样做很好，但感觉不对，更简单的方法是不做2选择。我想在那个循环中显示订单，因此每个订单都不会重复名称，电子邮件等。

Answer 1

我会用这样的left join来解决它：

<?php
  $query = $db->prepare(
    "SELECT *, preorder.title, preorder.number " .
    "FROM contact " .
    "LEFT JOIN preorder  ON (contact.contactid = preorder.contactid) " .
    "WHERE type = ? ORDER BY contactid, date")
  or die(mysqli_error($db));
  $type = "order";
  $query->bind_param('s', $type);
  $query->execute();
  $query->store_result();
  $query->bind_result($id, $name, $email, $date, $title, $number);

  $last_id = false;
  while ($query->fetch()) {
    $date = strtotime($date);
    $date = date("F jS  Y", $date);

    if ($contactid != $last_id) {
?>
        From: <?php echo $name ?>
        <input type="Checkbox" name="checkbox[]" 
               id="checkbox[]" value="<? echo $contactid; ?>"> 
        <p>
            <?php
            echo $comments
            ?>
        </p>
<?php
      echo $date;
    }
    echo $title, $number;
    $last_id = $contactid;
  }
?>

加入表格或2选择查询？

1 个答案: