mysql - php mysql pdo 从表单输入插入相关表

Question

三张相关表：一张表是member能够添加到另外两张表中的表（实际上其中一张是zip/city/state，称为location表，所以不需要插入），但第三张表postad是会员可以发布广告。

成员已登录并开始会话并被定向到postad表单，成员如何填充postad表。这些表格是：

member (id, username, email, address, locationId ...)
location (zip, state, county)
postad (id, title, descrip, locationId, memberId ...)

这是代码：

$post=array('title','descrip','locationid','memberid');
foreach ($_POST as $post => $var) $$post=$var; 

if ($_POST['submitted']) {

$stmt = $pdo->prepare("INSERT INTO `postad` (`title`,`descrip`,`locationid`,`memberId`) VALUES 
(:title,:descrip,(SELECT `id` FROM `location` WHERE `id` LIKE :id AND `member.id`=:memberid))")

echo "Thank you!"; 

}