php mysql_insert_id(); not working

Question

Hi guys I was hoping from some help here, please.

I have a INSERT query to a table, after this is done I am calling:

mysql_insert_id();

In order to send the last ID inserted into the table to the next page like this:

$insertGoTo = "confirm_booking.php?booking_ID=" .$_POST['booking_ID']. "";

Unfortunately it does not work, all I get is a zero.

The table I am inserting into has an auto increment number and values are inserted into it.

I have also tried SELECT MAX(id) FROM mytable. This dosn't work neither.

I know that this problem has been talked about already. I read all posts but nothing came useful.

Many thanks Francesco

Answer 1

You have to use the value returned by MySql_Insert_Id () when you generate your link:

// your query
$newId = MySql_Insert_Id ();

$insertGoTo = "confirm_booking.php?booking_ID=" . $newId;

Answer 2

Some key points from the PHP Manual:

The ID generated for an AUTO_INCREMENT column by the previous query on success, 0 if the previous query does not generate an AUTO_INCREMENT value, or FALSE if no MySQL connection was established.

If not having an AUTO_INCREMENT field is not your problem, you might want to try storing the result of the mysql_query call and using that as an argument to the id function

$result = mysql_query("...");
$id = mysql_insert_id($result);

Answer 3

May be your table has no AUTO_INCREMENT field!

Or. It could be if you use two or more mysql-connections. In this case you should link identifier.

$link = mysql_connect( ... );
mysql_select_db('mydb', $link);
mysql_query('INSERT mytable SET abc="123"', $link);
$inserted_id = mysql_insert_id($link);

Answer 4

mysql_insert_id may return 0 or false if your insert fails right? So if you have trouble with mysql_insert_id not retunring what you expect confirm that you don't have a unique constraint or some other problem with your sql that would cause the insert to fail. Using max is a terrible idea if you consider this.