$result->fetch_array(MYSQLI_NUM);

fetches each row of the result like this:

​

array(

    0 => "first_field_content",

    1 => "second_field_content"

);

Alternatively...

​

$result->fetch_array(MYSQLI_ASSOC);

fetches an array like this:

​

array(

    "first_field_name" => "first_field_content",

    "second_field_name" => "second_field_content"

);

​