sql的分页

public static string GetPageSql(string sql, int start, int end)
        {
            return string.Format(" select * from (select t1.*,rownum rowno from ({0}) t1 where rownum<={2}) t2 where t2.rowno>={1}",
                            sql, start, end);
        }

其中sql参数是查询所有的数据