查询错误 - 警告：mysqli_fetch_assoc（）

Question

<?php
$con=mysqli_connect("localhost","xxx","xxx","xx");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

$sql = mysqli_query($con,"SELECT username, COUNT(username) AS total FROM xxxxx GROUP BY username");

$array = array();
while($fetch = mysqli_fetch_assoc($sql))
{
    $array[$fetch['username']] = $fetch['total'];
}

echo '<pre>'; print_r($array);

mysqli_close($con);
?>

以下是我收到的错误

  

错误:::警告：mysqli_fetch_assoc（）期望参数1为   mysqli_result，第20行/home/xxxxx.php中给出的布尔值   

感谢您的帮助

Answer 1

尝试这不是mysql而是mysqli

while($fetch = sql->fetch_assoc())
{
......