Question

我尝试谷歌但是，我真的不明白这个查询有什么问题。这是代码

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!";
}

这个查询什么都没给我。只是这个错误mysqli_num_rows（）期望参数1是mysqli_result，在第8行给出的是布尔值，如果我删除ORDER BY DESC，第10行会有一些错误？对不起，如果重复，但我不知道解决这个问题！谢谢！

Answer 1

您的SQL语句没有ORDER列：

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

使用正确的列名更改它：

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

可能mysqli_query正在返回false而不是mysqli_result个对象。

Answer 2

添加segarci，

$row = mysqli_fetch_array($sql)

应该是

$row = mysqli_fetch_array($user_query)

Mysqli num行和mysqli获取数组问题

2 个答案: