优化：统计产品类数量。

forest-admin/admin-server/src/main/resources/dao/BigCompanyDao.xml

@@ -111,7 +111,7 @@
 
             FROM
                 pms_product b
-                LEFT JOIN pms_product_category c ON b.product_category_id = c.id 								GROUP BY c.id,b.ums_company_info_id
+                LEFT JOIN pms_product_category c ON b.product_category_id = c.id WHERE b.product_category_id IS NOT NULL GROUP BY c.parent_id,b.ums_company_info_id
 								union all
 
 								SELECT