I've tried to follow several answers on this question but can't seem to get it to work for my specific problem.
I want to insert data but only if the flight_number
doesn't exists already. How can I do that?
$sql = mysqli_query($con,
"INSERT INTO space (`flight_number`, `mission_name`, `core_serial`, `payload_id`)
VALUES ('".$flight_number."', '".$mission_name."', '".$core_serial."', '".$payload_id."')"
);