如何用mysql和php生成的json字符串替换回车?

I got stuck with the nuance:

我被这种细微差别困住了:

//1 - get mysql results into array
while ($row = mysqli_fetch_array($r, MYSQLI_ASSOC)) {

    array_push($my_array, $row['fruit_name']);

}

//2 - sort array
sort($my_array);

//3 - convert array to json
json_encode($my_array);
/