分页语句:
select * from (select * from (select * from user order by userName)
where rownum <= 20) where rownum >=1
在这里,如果排序字段userName是唯一的则不会出现问题,否则就会出现重复记录的问题。
解决办法是,如果不能确定排序字段是唯一的,必须添加另外一个排序字段,该字段最好是唯一索引键,如:
select * from (select * from (select * from user order by userName, userId)
where rownum <= 20) where rownum >=1