为啥pager.getRecordCount() 总是0

		Pager pager = new Pager();
		pager.setPageNumber((int) Math.ceil(offset / limit));
		pager.setPageSize(limit);
		Sql sql = Sqls.create(" select a.*,b.fName,b.fSpec,b.fAssist,b.fAssistText,b.fImage from SM_evaluate a left join PR_product b on b.fID =a.fProductID where a.fCustomerID =@userid ");
		sql.setParam("userid", userid);
		sql.setPager(pager);
		sql.setCallback(Sqls.callback.maps());
		dao.execute(sql);
		List<Map> rows = sql.getList(Map.class);
		System.out.println(pager.getRecordCount());//为啥得到总是0