Untitled


<!DOCTYPE html>
<html>
<body>

<form method="post">
<!--
Year: <input type="text" name="year"><br>
-->
Choose a date: <input type="number" name="year"><br>
Total or average salary:<br>

<select name="option">
    <option value="total">Total</option>
    <option value="average">Average</option>
</select>
<input type="submit">
</form>

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

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

    if(!$conn){
        exit("Error: could not reach database.");
    }
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}


// $year = $_POST['year']
$year = $_POST['year'];
$option = $_POST['option'];


$minyear = "SELECT MIN(LEFT(s.from_date,4))
            FROM salaries AS s
            GROUP BY s.from_date ASC";


if($option == 'total'){
    $sql = "SELECT SUM(s.salary) AS salary
            FROM salaries AS s
            WHERE $year = LEFT(s.from_date,4)";
} else{
    $sql = "SELECT SUM(s.salary)/COUNT(s.salary) AS salary
            FROM salaries AS s
            WHERE $year = LEFT(s.from_date,4)";
}


$resultat = mysqli_query($conn, $sql);
$minyearresultat = mysqli_query($conn, $minyear);

print('<table border="1">');
$rad = mysqli_fetch_assoc($resultat);
    if(min($minyearresultat) > $year){
        echo ("Please input correct year.");
    }else if ($resultat->num_rows > 0) {
    while($rad){
        $salary=$rad['salary'];
        echo ("<tr><td>$year</td><td>$salary</td></tr>");
        $rad = mysqli_fetch_assoc($resultat);
        }
    }else{
        echo "0 results.";
    }
    print('</table>');

    mysqli_close($conn);

?>


    </body>
</html>