Return MySQL data in JSON format

Here is the code for Return MySQL data in JSON format:

$con=mysqli_connect($servername,$username,$password,$databasename);
if (mysqli_connect_errno())
{
echo "Connection Error" . mysqli_connect_error();
}
$query = "SELECT * FROM TableName";
$result = mysqli_query($con,$query);
$querydata = array();
while($data = mysqli_fetch_array($result)) {
$querydata[] = $data;
}
echo json_encode($querydata);
mysqli_close($con);