普通情况对于有主键，能够做唯一表识的表。我们能够利用主键和rownum配合实现。比如：

select scott.emp.* from scott.emp left join         (select empno id, rownum num from scott.emp) id_num         on scott.emp.empno = id_num.id where id_num.num between 5 and 10;

假设遇到没有主键的表能够尝试rowid取代。rowid不会由于排序或者查询，甚至update都不会改动，因此能够借助这个字段作分页。

select scott.emp.* from scott.emp left join     (select rowid id, rownum num from scott.emp)  id_num     on scott.emp.rowid = id_num.id where id_num.num between 5 and 10;