Where can be MYSQL and PHP error?

Question

PHP

There is this line:

$query =mysql_query("SELECT * FROM usertbl WHERE username='".$username."' AND password='".$password."'");

Authorization does not work, query was empty error Tables exist, everything seems to be written correctly, but does not work

Answer 1

mysql_query() returns a handle to the query result (resource), or FALSE on error .

php.net/manual/ru/function.mysql-query.php
The word PASSWORD is reserved in MySQL. Therefore, you need to wrap the column name in backticks.

$username = htmlspecialchars($_POST['username']);
$password = htmlspecialchars($_POST['password']);
$query = mysql_query("SELECT * FROM usertbl WHERE username='".$username."' AND `password`='".$password."'");
if (!$query) {
    die('Ошибка: ' . mysql_error());
}
$numrows = mysql_num_rows($query);

Answer 2

Run a bare query in some mysql IDE - in the same phpMyAdmin, for example. If the request goes through normally, then the error is somewhere in PHP.