PHP选择登录错误

Question

I'm just a newbie in PHP and I need to create a php Login form but It have a syntax error saying Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in C:\xampp\htdocs\login.php on line 18
maybe you can help me on this tnx!

<?php

$con=mysqli_connect("localhost","root","","reservation");
if (mysqli_connect_errno())
  {
  echo "Failed to connect to Database: " . mysqli_connect_error();
  }
  else
  {
  }

if ($_POST["SUBMIT"]="SUBMIT")
{
$username = $_POST['username'];
$password =$_POST['password'];
$sql ="SELECT * FROM usersaccount where='$username' and password ='$password'";
$result=mysqli_query($con,$sql);
$count=mysqli_num_rows($result);
if($count==1)
{
echo "success";
}
//mysqli_close($con);
}
?>

Answer 1

Your SELECT statement is wrong ... should be

SELECT * FROM `usersaccount` WHERE `username` ='$username' and `password` ='$password'";
                                   ---------- // Here.. Added the column name

You are not providing the column name for username field. That was your issue. Since you are matching results with condition you need a WHERE clause too !

^{Disclaimer : Stop using mysql_* functions as they are deprecated. Switch to MySQLi or PDO instead.}