Using a single form inserting data into two differen tables though needing to insert last auto id from the first insert into the next

I have a form I need to insert some information into one table. Then grab the auto increment id from that insert and use it in the next insert statement. I get it all to work except for the grabbing the last id. mysql_insert_id()?

include("config.inc.php");
$link = mysql_connect($db_host,$db_user,$db_pass);
if(!$link) die ('Could not connect to database: '.mysql_error());
mysql_select_db($db_name,$link);
$query = "INSERT into `".$db_table."` (title_id,seg_ordering,seg_name,seg_开发者_开发技巧description,seg_duration) VALUES ('" . $_POST['title_id'] . "','" . $_POST['seg_ordering'] . "','" . $_POST['seg_name'] . "','" . $_POST['seg_description'] . "','" . $_POST['seg_duration'] . "')";
mysql_query($query);
mysql_close($link);





include("config.inc.php");
$link = mysql_connect($db_host,$db_user,$db_pass);
if(!$link) die ('Could not connect to database: '.mysql_error());
mysql_select_db($db_name,$link);


function select_max_id($id="id",$my_table="jos_mad_segments")
{


  $SQL = "SELECT MAX($seg_id) FROM ".$my_table;
  $db->query($SQL);
  if ($db->next_record())
  {
     $max_id = $db->f(0);
  }
$db->close();
return $max_id;
} 



//data insert 2 //

include("config2.inc.php");
$link = mysql_connect($db_host,$db_user,$db_pass);
if(!$link) die ('Could not connect to database: '.mysql_error());
mysql_select_db($db_name,$link);
$query = "INSERT into `".$db_table."` (seg_id,file_video_UNC,file_video_URL) VALUES ('" . '$max_id' . "','" . $_POST['file_video_UNC'] . "','" . $_POST['file_video_URL'] . "')";
mysql_query($query);
mysql_close($link);

You can fire max(auto_id) function on the table to get the last auto id from the table if Auto Id is integer type///