Oracle 枢轴是如何工作的？

count ( case when medal = 'Gold' then 1 end )

with rws as (
  select mod(rownum, 3) x from dual connect by level <= 10
)
  select * from rws
  pivot (count(*) for x in (0 as zero, 1 as one, 2 as two));

ZERO  ONE  TWO  
3     4    3    

select "from$_subquery$_003"."ZERO" "ZERO",
    "from$_subquery$_003"."ONE" "ONE",
    "from$_subquery$_003"."TWO" "TWO"
from
  (select nvl ( sum (
    case
      when ( "RWS"."X"=0 ) then 1
    end ) ,0 ) "ZERO",nvl ( sum (
    case
      when ( "RWS"."X"=1 ) then 1
    end ) ,0 ) "ONE",nvl ( sum (
    case
      when ( "RWS"."X"=2 ) then 1
    end ) ,0 ) "TWO"
  from
    ( select mod ( rownum,3 ) "X" from "SYS"."DUAL" "DUAL" connect by level<=10
    ) "RWS"
  ) "from$_subquery$_003"