for($k=0; ; $k++){
$random_code=rand(100000,999999);
$select = mysql_query("select * from `table` where `col` = '$random_code'");
$Row = mysql_fetch_array($select);
$col = $Row['col'];
if($col!=$random_code){
echo $random_code;
mysql_query("INSERT INTO table VALUES ('NULL','$random_code')");
break;
}
}
function code_generator() {
$time = time();
$random_string = str_shuffle('1234567890ABCDEF');
$code = hash('md5', $time.$random_string);
return strtoupper($code);
}
echo base_convert(code_generator(), 16, 10);