Fixed bug that total amount is showing negative when order with discount is partially refunded

Author: rav-redchamps

app/code/Magento/Reports/Model/ResourceModel/Order/Collection.php

@@ -773,8 +773,8 @@ public function addRevenueToSelect($convertCurrency = false)
             !$convertCurrency,
             $this->getConnection()->getIfNullSql('main_table.base_subtotal_refunded', 0),
             $this->getConnection()->getIfNullSql('main_table.base_subtotal_canceled', 0),
-            $this->getConnection()->getIfNullSql('main_table.base_discount_refunded', 0),
-            $this->getConnection()->getIfNullSql('main_table.base_discount_canceled', 0)
+            $this->getConnection()->getIfNullSql('ABS(main_table.base_discount_refunded)', 0),
+            $this->getConnection()->getIfNullSql('ABS(main_table.base_discount_canceled)', 0)
         );
         $this->getSelect()->columns(['revenue' => $expr]);
 
@@ -796,8 +796,8 @@ public function addSumAvgTotals($storeId = 0)
             $storeId,
             $this->getConnection()->getIfNullSql('main_table.base_subtotal_refunded', 0),
             $this->getConnection()->getIfNullSql('main_table.base_subtotal_canceled', 0),
-            $this->getConnection()->getIfNullSql('main_table.base_discount_refunded', 0),
-            $this->getConnection()->getIfNullSql('main_table.base_discount_canceled', 0)
+            $this->getConnection()->getIfNullSql('ABS(main_table.base_discount_refunded)', 0),
+            $this->getConnection()->getIfNullSql('ABS(main_table.base_discount_canceled)', 0)
         );
 
         $this->getSelect()->columns(
@@ -827,8 +827,8 @@ protected function getTotalsExpression(
         $baseDiscountCanceled
     ) {
         $template = ($storeId != 0)
-            ? '(main_table.base_subtotal - %2$s - %1$s - ABS(main_table.base_discount_amount) + %3$s + %4$s)'
-            : '((main_table.base_subtotal - %1$s - %2$s - ABS(main_table.base_discount_amount) + %3$s + %4$s) '
+            ? '(main_table.base_subtotal - %2$s - %1$s - (ABS(main_table.base_discount_amount) - %3$s - %4$s))'
+            : '((main_table.base_subtotal - %1$s - %2$s - (ABS(main_table.base_discount_amount) - %3$s - %4$s)) '
                 . ' * main_table.base_to_global_rate)';
         return sprintf($template, $baseSubtotalRefunded, $baseSubtotalCanceled, $baseDiscountRefunded, $baseDiscountCanceled);
     }