9일차 # Pseudocolumn

# Pseudocolumn ==> http://goo.gl/NKgL8  참고하세요.

   : behaves like a table column, but is not actually stored in the table

  select rownum as no, empno, ename, sal

  from emp;

  select rownum as no, empno, ename, sal

  from emp

  where rownum <= 3;

  select rownum as no, rownum*2 as no2, rownum*10 as no3

  from emp

  where rownum <= 3;

  select rownum, rowid, empno, ename, sal

  from emp;