【一个有意思的输出】

SQL> select decode
  2  ( sign(floor(maxwidth/2)-rownum)
  3  , 1, lpad( ' ', floor(maxwidth/2)-(rownum-1))
  4  || rpad( '*', 2*(rownum-1)+1, ' *')
  5  )
  6  from all_objects,
  7  (select 10 as maxwidth from dual)
  8  where rownum

DECODE(SIGN(FLOOR(MAXWIDTH/2)-ROWNUM),1,LPAD('',FLOOR(MAXWIDTH/2)-(ROWNUM-1))||R
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