SQL> with a as
  2  (select rownum p from dual connect by level <=21)
  3  select
  4   7+ ceil (
  5    ( 7+ ceil (
  6    ( 7+ ceil(p/3))
  7    /3))
  8    /3)
  9  from a;

7+CEIL((7+CEIL((7+CEIL(P/3))/3))/3)                                            
-----------------------------------                                            
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                                11                                                                                                             
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                                 11                                            

已选择21行。