<?
$q = "SELECT * FROM tableName WHERE user = 'abc' AND a = '0' AND b = '0'";
$r = mysql_fetch_object(mysql_db_query($dbname,$q,$dblink));

if ($r->id != 0){
$id = $r->id;
}else {
$q = "INSERT INTO tableName SET user = 'abc', a = '0', b = '0'";
$r = mysql_db_query($dbname,$q,$dblink);
$id = mysql_insert_id();
}
?>

ako pravilno sym te razbral taka shte stane s nai-mnogo dve .. :)

unF ..