Primary Key of the DB as PHP header info - php

Question

I have created a registration form which is in application.php and when submitted it is processed and the contents are stored using submit.php and I want to redirect to thanks.php with a parameter called message with value equal to the primay key of the recently inserted row.. For example it should return my 100th applicant to the page,
www.mydomain.com/thanks.php?message=100
where 100 is the Primary key (AI).
In other words I want to print the primary key of the table as a refernce id for the users.. I tried
header("location: thanks.php?message=".$id); and
header("location: thanks.php?message=".$_POST['id']);
Both dont work for me.
Kindly help me guys!
EDIT:
require("admin/sources/connection.php");
$id = mysql_insert_id();
// Other variables are declared here
$sql = "my_INSERT_query_goes_here";
$result = $conn->query($sql);
if($result) {
header("location: thanks.php?message=".$id);
}
This is my submit.php code

Answer 1

Wrong execution order - simple fix
You are first assigning $id, and then running the query.
Twist them around to make it work.
Not using auto-increment?
I see in the query in your comment, that you manually pass the id you want to enter. Did you realize that mysql_insert_id() will not return the sql column that you did call "id", but the column that you set an auto-increment on? That is a single row in your table that automaticly gets an incrementing number without the need to manually enter it.

Answer 2

Couple issues ... it looks like you're mixing mysql_ methods with mysqli and you have the execution in the wrong order.
If your database table is auto-increment, you don't need to pass an ID in the query. By calling $id = mysql_insert_id(); and using the id in the query, you're passing in 0 as the id which uses the next auto-increment id.
Getting the insert_id after $conn->query($sql); will return to you the insert id used.
Echo some variables to see what values you're getting for mysql_insert_id(); before and after.
However, if you're doing a $conn->query(), then you're not using the standard mysql_ functions.
Try this:
require "admin/sources/connection.php";
// Other variables are declared here
$sql = "my_INSERT_query_goes_here";
$result = $conn->query($sql);
if($result) {
$id = $conn->insert_id;
header("location: thanks.php?message=".$id);
}