var_dump returns bool(false)

I am absolute beginner with php and mysql .. i want to put (year, month, demand) in the (table) in database but var_dump shows Bool(false) and nothing is being passed to the database ... it is also shows successfully registered alert. here is my full code

<html>
    <head>
        <title>Simulation</title>
    </head>
    <body>
        <h2>Registration Page</h2>
        <a href="home.php"> Click here to go back </a><br/><br/>
        <form action="register.php" method="POST">
           Enter year: <input type="number" name="year" required="required" /> <br/>
           Enter month: <input type="number" name="month" required="required" /> <br/>
           Enter demand: <input type="number" name="demand" required="required" /> <br/>
           <input type="submit" value="Register"/>
        </form>
    </body>
</html>

<?php
    if ($_SERVER["REQUEST_METHOD"] == "POST")
    {
        $year = mysql_real_escape_string ($_POST['year']);
        $month = mysql_real_escape_string ($_POST['month']);
        $demand = mysql_real_escape_string ($_POST['demand']);

        echo " year is" .$year. "<br/>";
        echo " month is" .$month. "<br/>";
        echo " demand is" .$demand;

        mysql_connect("localhost", "root","") or die(mysql_error()); //Connect to server
        mysql_select_db("first_db") or die("Cannot connect to database"); //Connect to database

        $qu = mysql_query("INSERT INTO table (year, month, demand) VALUES ('$year','$month','$demand')"); //Inserts the value to table users
        var_dump ($qu);
        die();
        Print '<script>alert("Successfully Registered!");</script>'; // Prompts the user
        Print '<script>window.location.assign("register.php");</script>'; // redirects to register.php
    }

?>

Solution

table is reserved word and you must change your table name and use below query:

INSERT INTO Table_Name (year, month, demand) VALUES ('$year','$month','$demand')