Java中用sql 联合查询出现有关问题，求解

select b.*,e.uid,e.ip,e.place,e.ctime,count(distinct e.uid) from edm.edm_open_56 e left join (select u.id,u.email from e_toemail u ) b on e.uid = b.id

public List<EmailOpenReturnInfoVO> findOpenInfo(Long taskId) {        List<EmailOpenReturnInfoVO> emailOpenReturnInfoVOs = new ArrayList<EmailOpenReturnInfoVO>();        String sql = "select b.*,e.uid,e.ip,e.place,e.ctime,count(distinct e.uid) from edm.edm_open_56 e left join (select u.id,u.email from e_toemail u ) b on e.uid = b.id";        PreparedStatement ps = null;        ResultSet rs = null;        EmailOpenReturnInfoVO vo = null;        Session session = null;        try {            session = this.sessionFactory.openSession();            ps = SessionFactoryUtils.getDataSource(session.getSessionFactory()).getConnection().prepareStatement(sql);            rs = ps.executeQuery();            while (rs.next()) {                vo = new EmailOpenReturnInfoVO();                vo.setEmial(rs.getString("email"));                vo.setIp(rs.getString("ip"));                vo.setPlace(rs.getString("place"));                vo.setTime(new Date(rs.getInt("ctime")*1000L));                emailOpenReturnInfoVOs.add(vo);            }        } catch (SQLException e) {            e.printStackTrace();        } finally {            if(null != session)                session.close();        }        return emailOpenReturnInfoVOs;    }