printing br / when there is no data in database code example

Example: print data that will be inserted in the database

$key = strtoupper(c_security::random_string(22));
$c_con->query("INSERT INTO keys(key, days, used) VALUES ('$key',".c_security::anti_sql_string($_POST["daysammount"])."', '0')");
echo $key;
i think like that