FINALLY
i wrote a function to generate a random unique number in a mysql table
looks simple
but my brain was about to crash,
wondering if i have

function unique_row_serial($table){
$is_made='no';
$min=10000000;
$max=99999999;
while( $is_made=='no' ){
$number=mt_rand($min,$max);
$query=mysql_query("SELECT * FROM `".$table."` WHERE `serial`='".$number."'");
if(mysql_num_rows($query)<1){$is_made='yosh';}
}
return $number;
}