我得到这一呼吁说一个成员函数fetch_array布尔线错误()23. 线23由该行代码FETCH_ASSOC()错误
$row = $query->fetch_assoc();
这里是整个块
if(!filter_has_var(INPUT_GET, 'id')) {
echo "Error: book id was not found.";
require_once ('includes/footer.php');
exit();
}
$book_id = filter_input(INPUT_GET, 'id', FILTER_SANITIZE_NUMBER_INT);
$sql = "SELECT * FROM books WHERE book_id=" . $book_id;
$query = $conn->query($sql);
$row = $query->fetch_assoc();
echo'$ sql =“SELECT * FROM books WHERE book_id =”。 $ book_id; '检查你的查询 – Saty