当我让它工作时我很高兴，但它会提交两次订单，除非我注释掉最后两行。有没有更好的方法来编写它，这样我就不会重复？
$sql = "INSERT INTO orders (weight, shipper, shipacct) VALUES ('$weight', '$shipper', '$shipacct')";
$conn->query($sql);
$recordid = $conn->insert_id;
我这样做是因为我试图使用记录 ID 作为订单 ID。我在购买收据上将此订单 ID 回显给客户。
更新代码：
$sql = "INSERT INTO orders (weight, shipper, shipacct) VALUES ('$weight', '$shipper', '$shipacct')";
$recordid = mysql_insert_id();
没有重复，但不返回记录 ID。
警告
This extension is deprecated as of PHP 5.5.0, and will be removed in the future.
Instead, the MySQLi or PDO_MySQL extension should be used.
See also MySQL: choosing an API guide and related FAQ for more information.
Alternatives to this function include:
mysqli_insert_id()
PDO::lastInsertId()
尝试以下操作：
$sql = "INSERT INTO orders (weight, shipper, shipacct) VALUES ('$weight', '$shipper', '$shipacct')";
$conn->query($sql);
$recordid = mysql_insert_id();
注意：
因为 mysql_insert_id() 作用于最后执行的查询，所以确保在生成值的查询之后立即调用 mysql_insert_id()。