Mysqli行数和mysqli获取数组问题

Question

我试着用谷歌搜索一下，但我真的不明白这个查询有什么问题。以下是代码

include_once("includes/db_connection.php");
//Upit za prikaz pitanja!
$listaPitanja = "";
$sql = "SELECT id, username, question FROM useroptions ORDER BY DESC";
$user_query = mysqli_query($db_connection, $sql);
$pitanjaCount = mysqli_num_rows($user_query); //line 8
if ($pitanjaCount > 0) {
while ($row = mysqli_fetch_array($sql))  { //line 10
$id = $row['id'];
$question = $row['question'];
$username = $row['username'];
$listaPitanja .= '<div id="brojOdgovora">'.$id.'</div>
            <div id="tekstPitanja"><h3>'.$question.'</h3></div>
            <div id="userPitanja"><h6>'.$username.'</h6></div>';
    } 
} else {
$listaPitanja = "There is no inserted questions!";
}

这个查询没有给我任何帮助。就是这个错误，mysqli_num_rows()期望参数1为mysqli_result，布尔值在第8行，如果我删除了ORDER BY DESC，第10行是否有错误？如果重复了，很抱歉，但我不知道如何解决这个问题！谢谢!

Answer 1

您的SQL语句没有ORDER列：

$sql = "SELECT id, username, question FROM useroptions ORDER BY DESC";

将其更改为正确的列名：

$sql = "SELECT id, username, question FROM useroptions ORDER BY column_name DESC";

很可能，mysqli_query返回的是false而不是mysqli_result对象。

Answer 2

为了添加segarci，

$row = mysqli_fetch_array($sql) 

应该是

$row = mysqli_fetch_array($user_query)