从php-mysql表中删除数据

我有两个表，如果可能的话，我想同时update和via 1 query。我有一个customer table，其中primary key of cusomerid被设置为自动递增，而complaints table中customerid被设置为foreign key.

我想从客户表中删除，简单地说，当我删除该客户时，它也应该从投诉表中删除。希望这是有道理的。有人能解释一下如何实现我的上述两个目标吗？

    <?php
include("functions.inc.php");
display_header("Delete a record");
?>
<?php
require_once("dbconnect.inc.php");
?>
<!--displays array easier to read-->
<?php //echo '<pre>';?>  
<div id="container">
<header><?php include("header.inc.php");?></header>
<nav><?php include("navbar.inc.php");?></nav>
<?php include("sidebar.inc.php");?>
<p>
    <img src="images/relationsimage.PNG"/>

    <form action="delete.php" method="post"> 
<?php
$query = "SELECT * FROM customer";
$resultset = $conn->query($query);
while ($row = $resultset->fetch())
{
 echo "<p>";
echo "<input type='checkbox' name='customer[]' id='customer".$row['customerid']."' value='".$row['customerid']."'>";
echo "<label for='customer".$row['customerid']."'>".$row['title']." ".$row['forename']." ".$row['surname']." ".$row['roadname']." ".$row['town']." ".$row['county']." ".$row['postcode']." ".$row['phonenumber']." ".$row['paymentmethod']."</label>";
echo "</p>";
}
?>

<input type="submit" value="delete these sales leads">
</form>
 <?php   
    if (!isset($_POST['customer']))
{
   echo "";
   exit;
}

    $query="DELETE FROM customer WHERE customerid=:customerid";
    $pr_stmt=$conn->prepare($query);
$affected_rows=0;
foreach($_POST['customer'] as $cusid)
{
    $pr_stmt->bindValue(':customerid',$cusid);
    $affected_rows += $pr_stmt->execute();  
}
echo "Deleted ".$affected_rows." customer from customers table";
$conn=NULL; //close the connection
?>
</p>

<footer><?php include("footer.inc.php");?></footer> 
</div>
</body>
</html>