fix

internal/modules/purchases/services/purchase.service.go

@@ -264,6 +264,14 @@ func (s *purchaseService) GetAll(c *fiber.Ctx, params *validation.Query) ([]enti
 
 		sortBy := strings.TrimSpace(params.SortBy)
 		sortOrder := strings.ToUpper(strings.TrimSpace(params.SortOrder))
+
+		if sortBy == "" && (filterBy == "po_date" || filterBy == "due_date" || filterBy == "received_date" || filterBy == "created_at") {
+			sortBy = filterBy
+			if sortOrder == "" {
+				sortOrder = "ASC"
+			}
+		}
+
 		if sortOrder == "" {
 			sortOrder = "DESC"
 		}