php - fatal error : [] Operator not working on one page but working on another

Question

我的代码说我收到以下错误: fatal error :[] operator not supported for strings in

问题是，我在成员(member)页面上使用了相同的代码，但是当我将它包含在我的相册页面上时，却出现了错误。 PHP:

$sql = "SELECT *, song_genres.genre FROM favoriteband JOIN song_genres ON favoriteband.band_name = song_genres.band_name WHERE favoriteband.username = '$username'";
$query = mysqli_query($conn, $sql); #query

# If user has not favorited bands
$rows_returned = mysqli_num_rows($query);

if ($rows_returned < 1) { ?>

    <tr>
        <th>For Recommendations,<br> Start Liking Bands</th>
    </tr>

<?php } else {

# Loop through each song
while ($row = mysqli_fetch_array($query)){
    $username = $row['username'];               # Loop Username
    $band_name[] = $row['band_name'];       # Get the Band Name
    $genre[] = $row['genre'];               # Get the Genres for each band
}

// The error is fond on $band_name[] = $row['band_name'];
// Also $rows_returned shows 77 rows, so it does produce multiple values.

这是 HTML:

<?php if (isset($_SESSION['username'])){ ?>
<!-- MEMBER RECOMMENDATIONS -->
<table style="width: 90%; margin: 0 auto;">
    <tr >
        <th style="background: green; color: #fff;" colspan="2">My Recommendations</th>
    </tr>
    <?php include ("process/memberRecommendation.php"); ?>
</table>
<?php } ?>

成员(member)页面有效，专辑页面无效。这让我感到困惑，因为如果它工作一次，它应该总是工作相同。

Answer 1

$band_name = $row['band_name']; //works
$genre = $row['genre'];   //works

然后，如果您将字符串视为数组，它将给出 fatal error :

$bandname[] = 'string'; // fatal error

只需在开头添加这个即可修复该错误

$band_name = array();
$genre = array();