oracle中的rownum

create table person(ID char(6), name VARCHAR2(100));
insert into person values('200001',‘徐一’);
insert into person values('200002',‘李二’);
insert into person values('200003',‘張三’);
insert into person values('200004',‘小四’);

commit;

等於1：select rownum,id,name from student where rownum=1;

大於2：select * from(select rownum no ,id,name from student) where no>2;

閉區間：select * from (select rownum no,id,name from student where rownum<=3 ) where no >=2;

rownum僞列，每次查詢都是從1開始，因此要想查詢，大於或者區間須要用子查詢。