Database connection + query

<?php
$servername = "localhost";
$username = "root";
$password = "shaorma";
$dbname = "curswd";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// $sql = "SELECT id, firstname, lastname FROM MyGuests";
$sql = "SELECT name, spec FROM Students WHERE spec='IE' ORDER BY name";
$sql2 = "SELECT COUNT(*) FROM Students WHERE spec='IE'";
$sql3 = "SELECT Students.name, gradeWD.grade FROM Students, gradeWD WHERE Students.id = gradeWD.student";
$result = $conn->query($sql);
$result2 = $conn->query($sql2);
$result3 = $conn->query($sql3);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "Name: " . $row["name"]. " - Spectacol: " . $row["spec"]. "<br />";
    }
} else {
    echo "0 results";
}

if ($result2->num_rows > 0) {
    while($row = $result2->fetch_assoc()) {
        echo "Nr. of students: " . $row["COUNT(*)"]. "<br />";
    }
} else {
    echo "0 results";
}
echo "<br />";
if ($result3->num_rows > 0) {
    while($row = $result3->fetch_assoc()) {
        echo "Name: " . $row["name"]. " - Grade: " . $row["grade"]. "<br />";
    }
} else {
    echo "0 results";
}
$conn->close();
?>