sql语句实现分页技术

下面是三层嵌套的sql语句，使用其可以实现web前端的分页效果，要注意书写格式

select user_id, user_name, password, contact_tel, email, create_date from( select rownum rn, user_id, user_name, password, contact_tel, email, create_date from ( select user_id, user_name, password, contact_tel, email, create_date from t_user where user_id <> 'root' order by user_id ) where rownum <= 4 ) where rn > 1

示例：

/** * 分页查询 * @param pageNo 第几页 * @param pageSize 每页多少条数据 * @return pageModel */ public PageModel<User> findUserList(int pageNo, int pageSize){ StringBuffer sbSql = new StringBuffer(); sbSql.append("select user_id, user_name, password, contact_tel, email, create_date ") .append("from ") .append("( ") .append("select rownum rn, user_id, user_name, password, contact_tel, email, create_date ") .append("from ") .append("( ") .append("select user_id, user_name, password, contact_tel, email, create_date from t_user where user_id <> 'root' order by user_id ") .append(") where rownum <= ? ") .append(") where rn > ? "); Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; PageModel<User> pageModel = null; try{ conn = DbUtil.getConnection(); pstmt = conn.prepareStatement(sbSql.toString()); pstmt.setInt(1, pageNo * pageSize); pstmt.setInt(2, (pageNo - 1) * pageSize); rs = pstmt.executeQuery(); List<User> userList = new ArrayList<User>(); while (rs.next()){ User user = new User(); user.setUserId(rs.getString("user_id")); user.setUserName(rs.getString("user_name")); user.setPassword(rs.getString("password")); user.setContactTel(rs.getString("contact_tel")); user.setEmail(rs.getString("email")); user.setCreateDate(rs.getTimestamp("create_date")); userList.add(user); } pageModel = new PageModel<User>(); pageModel.setList(userList); pageModel.setTotalRecords(getTotalRecords(conn)); pageModel.setPageSize(pageSize); pageModel.setPageNo(pageNo); }catch(SQLException e){ e.printStackTrace(); }finally{ DbUtil.close(rs); DbUtil.close(pstmt); DbUtil.close(conn); } return pageModel; }