11-12 引き算でGO

SQLパズル

最初に四角形を書きます。
下の図のように、その４つの頂点の上に、それぞれ適当な数字を書きます。




次に４つの辺の中点を結んだ四角形を書いて、
その頂点に、それぞれ隣り合った数字の差を書き入れます。




さらに、今書いた四角形の中点を結んだ四角形を書いて、
その頂点に、それぞれ隣り合った数字の差を書き入れます。




同じ操作を続けると、




上の図のように、４つの数字が全部「０」になってしまします。
今回は、４回で、全部「０」になりましたが、
これをできるだけ「０」にしないように続けて下さい！
目標１０回以上です！

引き算でGO

SQL

select List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select abs(a-b) as a,abs(b-c) as b,abs(c-d) as c,abs(d-a) as d,List from(
select a.Val as a,b.Val as b,c.Val as c,d.Val as d,
to_char(a.Val) || ',' || to_char(b.Val) || ',' || to_char(c.Val) || ',' || to_char(d.Val) as List
  from (select RowNum as Val from all_catalog where RowNum <= 15) a,
       (select RowNum as Val from all_catalog where RowNum <= 15) b,
       (select RowNum as Val from all_catalog where RowNum <= 15) c,
       (select RowNum as Val from all_catalog where RowNum <= 15) d
 where a.Val <= c.Val and b.Val <= d.Val
   and a.Val <= b.Val)
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0!= any(a-b,b-c,c-d,d-a))
where 0 = all(a-b,b-c,c-d,d-a);

解説

インラインビューで差を求めてます。

---