fix: Group by filter fix in item wise sales and purchase register
diff --git a/erpnext/accounts/report/item_wise_purchase_register/item_wise_purchase_register.py b/erpnext/accounts/report/item_wise_purchase_register/item_wise_purchase_register.py
index 127f313..1f78c7a 100644
--- a/erpnext/accounts/report/item_wise_purchase_register/item_wise_purchase_register.py
+++ b/erpnext/accounts/report/item_wise_purchase_register/item_wise_purchase_register.py
@@ -102,7 +102,7 @@
 
 		data.append(row)
 
-	if filters.get('group_by'):
+	if filters.get('group_by') and item_list:
 		total_row = total_row_map.get(prev_group_by_value or d.get('item_name'))
 		total_row['percent_gt'] = flt(total_row['total']/grand_total * 100)
 		data.append(total_row)
diff --git a/erpnext/accounts/report/item_wise_sales_register/item_wise_sales_register.py b/erpnext/accounts/report/item_wise_sales_register/item_wise_sales_register.py
index 0c8957a..92a22e6 100644
--- a/erpnext/accounts/report/item_wise_sales_register/item_wise_sales_register.py
+++ b/erpnext/accounts/report/item_wise_sales_register/item_wise_sales_register.py
@@ -111,7 +111,7 @@
 
 		data.append(row)
 
-	if filters.get('group_by'):
+	if filters.get('group_by') and item_list:
 		total_row = total_row_map.get(prev_group_by_value or d.get('item_name'))
 		total_row['percent_gt'] = flt(total_row['total']/grand_total * 100)
 		data.append(total_row)