MySql: Function to insert entry and return id... if already exists, return id of existing?

[eluser]inktri[/eluser]
possible to do better than something like:?

Code:

<?php
$query = mysql_query("SELECT entryID FROM table WHERE {condition}");

//If it does exist
if (mysql_num_rows($query) > 0){
   $row = mysql_fetch_assoc($query);
   echo "Entry already exists, the id is {$row['entryID']}";

//if it doesn't exist
} else {
  
   //insert entry to DB
   $insert = mysql_query("INSERT INTO table (...) VALUES (...)");
   $id = mysql_insert_id();
  
   echo "New entry added, the id of the new entry is $id";
}

?>