Adding points and then show balance - php

Question

I have something like this on my website. and I want to calculate the whole points of Sofia and show her the total balance. which is 163. but I am not getting how to add and then show her balance on my website. sorry, if it is too easy question. I am new to php.
here is the code
<form method="POST">
user name : <input type="text" name="username"><br>
Points to Add: <input type="number" name="blance" max="100"
min="1">
<br>
<input type="submit" name="submit">
</form>
<?php
if (isset($_POST['submit'])) {
$servername = "localhost";
$user = "root";
$password = "";
$database = "enter code here";
$con = mysqli_connect("$servername", "$user" , "$password" ,
"$database");
if ($con->connect_error) {
die ("connection failed" . $con->connect_error);
} else {
$username = mysqli_real_escape_string($con, $_POST['username']);
$blance = mysqli_real_escape_string($con, $_POST['blance']);
$sql = "INSERT INTO user (username, blance) VALUES ('$username',
'$blance')";
if ($con->query($sql) === TRUE) {
echo "success";
} else {
echo "error" . $sql . "<br>" . $con->error;
}
$sql6 = "SELECT * FROM user";
$result = mysqli_query($con, $sql6);
$resultcheck = mysqli_num_rows($result);
if ($resultcheck > 0) {
while ($row = mysqli_fetch_assoc($result)) {
echo $row['username'] . "<br>";
}
}
echo "<br>" . "<br>" . "<br>";
}}
?>
</body>

Answer 1

This query will return sum of points for each username, assuming your table is named test
SELECT SUM(points) AS total_points
FROM test
GROUP BY username