Add default values for largest income/invoice month to 0. This fixes undefined errors and makes the chart show properly

report_income_summary.php

@@ -22,6 +22,10 @@ $sql_payment_years = mysqli_query($mysqli,"SELECT DISTINCT YEAR(payment_date) AS
 
 $sql_categories = mysqli_query($mysqli,"SELECT * FROM categories WHERE category_type = 'Income' AND company_id = $session_company_id ORDER BY category_name ASC");
 
+// Default values
+$largest_income_month = 0;
+$largest_invoice_month = 0;
+
 ?>
 
 <div class="card card-dark">
@@ -178,6 +182,7 @@ var myLineChart = new Chart(ctx, {
                 pointBorderWidth: 2,
                 data: [
                     <?php
+
                     for ($month = 1; $month<=12; $month++) {
                     $sql_payments = mysqli_query($mysqli,"SELECT SUM(payment_amount) AS payment_amount_for_month FROM payments, invoices WHERE payment_invoice_id = invoice_id AND YEAR(payment_date) = $year AND MONTH(payment_date) = $month AND payments.company_id = $session_company_id");
                     $row = mysqli_fetch_array($sql_payments);