获取msqli字段的结果计数

Question

我想获取mysqli查询结果的行数，但此代码不返回任何内容。

$mysqli = new mysqli('127.0.0.1', 'root', 'pass', 'db');
$sql = "SELECT * FROM user WHERE username = '".$_POST['username']."'";
$result = $mysqli->query($sql);

if($result->num_rows == 0){
  echo "0";
}else{
  $query = "INSERT INTO user (username,password) VALUES ('".$_POST['username']."','".md5($_POST['pass'])."')";
  if($mysqli->query($query)){
    echo "1";
  }else{
    echo "2";
  }
}

Answer 1

$mysqli = new mysqli('127.0.0.1', 'root', 'pass', 'db');
$sql = "SELECT * FROM user WHERE username = '".$_POST['username']."'";
$result = $mysqli->query($sql);
$rowcount=mysqli_num_rows($result);
echo $rowcount;

if($rowcount == 0)
{
echo "0";
}

else
{

$query = "INSERT INTO user (username,password) VALUES ('".$_POST['username']."','".md5($_POST['pass'])."')";

if($mysqli->query($query)
{
echo "1";
}
else
{
echo "2";
}

}