id | postcode | total
0  |  w1a 1aa | 2
1  |  g74 1bc  | 1
2  |  ml10 6qd  | 1

id | postcode | total

// connect to db
$servername = "localhost";
$username = "";
$password = "";
$dbname = "postcodes";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

foreach($csv as $row) {

    $postcode = $row[0];

    $sql = 'INSERT INTO postcodes VALUES (NULL, "'.$postcode.'", 1)';

    if (mysqli_query($conn, $sql)) {
        echo "New record created successfully";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }

}