PHP social contribution Yearly - php

Question

I'm working on a system report using PHP. I have a table with two columns (payment date and amount).
How I can use a while loop to calculate the total amount after each December through years? I tried to do it as per the screenshot attached but it displays the wrong sum after each December.
Below is how I did it:
<?php
$total=0;
$s = date('m');
$c = mysqli_query($con,"SELECT * FROM payroll_contribution_pssf WHERE employee_id='3' ORDER BY contribution_id ASC");
while($array = mysqli_fetch_array($c))
{
$m = date('m', strtotime($array['payroll_date']));
echo $array['payroll_date']." ".$array['employee_amount']."<br>";
if($m==12)
{
if($total == 0)
$total = $array['employee_amount'];
$total = $total + $array['employee_amount'];
echo number_format($total,0)."<br>";
}
}
?>

Answer 1

It seems you want it to calculate and display the total value of all the previous rows since the last total was calculated (or since the start of the dataset, in the case of the first iteration).
In that case the flaws in your logic are that you're
a) only adding to the total when it's the 12th month, and
b) you're not resetting it after you've reached the 12th month.
You need to have a "total" variable which is incremented each time you loop, and also you need to reset it to 0 after displaying it.
For example:
$total = 0;
$c = mysqli_query($con,"SELECT * FROM payroll_contribution_pssf WHERE employee_id='3' ORDER BY contribution_id ASC");
while ($array = mysqli_fetch_array($c))
{
$m = date('m', strtotime($array['payroll_date']));
echo $array['payroll_date']." ".$array['employee_amount']."<br>";
$total += $array['employee_amount']; //increment every time
if ($m == 12)
{
echo number_format($total, 0)."<br>";
$total = 0; //reset after displaying
}
}