php while循环不适用于用户定义的函数

Question

This way the while loop works fine:

$results = mysqli_query($dbcon, "SELECT `name`, `date` FROM `table1` WHERE `user` = $user_id);

while($data = mysqli_fetch_array($results)) {
    echo '<tr>
        <td>' . $data['name'] . '</td>
        <td>' . $data['date'] . '</td>
        </tr>'
}

However it does not want to work with user-defined function. It's just looping first row infinitely:

function camp_data() {
    global $user_id;
    $query = mysqli_query($dbcon, "SELECT `name`, `date` FROM `table1` WHERE `user` = $user_id");
    return (mysqli_fetch_array($query));
}

while($data = camp_data()) {
    echo '<tr>
        <td>' . $data['name'] . '</td>
        <td>' . $data['date'] . '</td>
        </tr>'
}

When I do print_r(mysqli_fetch_array($results)) and print_r(camp_data()) - both return absolutely identical array. What is wrong here?

Answer 1

No matter how much times you are calling the function externally, it will perform mysqli_fetch_array() only on the first row. Calling the function second time (on the second iteration in the external loop) will not know that it was executed before and will not proceed to the next row. Also looping with while on array is not the best choice you can have, it may result to an infinite loop.

You have to loop through the results in your function and build an array of them. Returning mysqli_fetch_array, is not looping.

while($data = mysqli_fetch_array($results)) {
    $rows[] = $data;
}
return $rows

And then perform foreach() on your function:

foreach (camp_data() as $data) {
   echo '<tr>
    <td>' . $data['name'] . '</td>
    <td>' . $data['date'] . '</td>
    </tr>'
}