如果特定列中不存在值，则将数据插入数据库

Question

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."')"
);

Answer 1

Rob since you saying flight_number is a unique then you can use INSERT IGNORE

<?php


    $sql = "INSERT IGNORE INTO space (`flight_number`, `mission_name`, `core_serial`, `payload_id`) VALUES (?,?,?,?)";

    $stmt = $con->prepare($sql);
    $stmt->bind_param('isss',$flight_number,$mission_name,$core_serial,$payload_id);
    if($stmt->execute()){

        echo 'data inserted';
        // INSERT YOUR DATA
    }else{

        echo $con->error;
    }

?>

OR you could select any row from your database that equal to the provided flight number then if u getting results don't insert.

$sql = "SELECT mission_name WHERE flight_number = ? ";
    $stmt = $con->prepare($sql);
    $stmt->bind_param('i',$flight_number);
    if(mysqli_num_rows($stmt) === 0){


        // INSERT YOUR DATA
    }