包含AS的SQL SELECT語句

Question

我有SQL查詢：

select title, scale / next_scale, c
from ( select title, scale, scale*D0 AS c, 
              lead(scale) over(partition by title order by scale asc) as next_scale,
              row_number() over(partition by title order by scale asc) as agg_row
       from signatures
     ) agg
where agg_row = 1;

並且它按預期工作。 但是，我真正希望排序的“標度”值是幾列之間的算術運算，因此我嘗試使用AS子句（如上所示）並將查詢修改為：

select title, scale / next_scale, c
from ( select title, scale, scale*D0 AS c, 
              lead(scale) over(partition by title order by c asc) as next_scale,
              row_number() over(partition by title order by c asc) as agg_row
       from signatures
     ) agg
where agg_row = 1;

但是，它在ORDER BY c處失敗。 為什么是這樣？ 我可以用ORDER BY scale*D0代替它，效果很好。 但是，我最終將要使用這樣的術語： scale*D0*D1*D2*...*D100 ; 而且我不需要計算3次不同的時間-更不用說查詢的物理長度了。 我希望具有scale*D0*D1*D2*...*D100 AS c ，然后具有ORDER BY c 。

這可能嗎？

我正在使用PostgreSQL。

非常感謝，布雷特

Answer 1

在子查詢中計算c ：

select title, scale / next_scale, c
from ( select title, scale, c, 
              lead(scale) over(partition by title order by c asc) as next_scale,
              row_number() over(partition by title order by c asc) as agg_row
       from (select title, scale, scale * D0 AS c from signatures) signatures_calc
     ) agg
where agg_row = 1;

Answer 2

您可以按列的序號ORDER BY：

select title, scale / next_scale, c
from ( select title, scale, scale*D0 AS c, 
          lead(scale) over(partition by title order by scale asc) as next_scale,
          row_number() over(partition by title order by scale asc) as agg_row
   from signatures
 ) agg
where agg_row = 1
order by 3;

Answer 3

下訂單時是子查詢，應填寫帳單

select title, scale / next_scale, c
from ( select title, scale, scale*D0 AS c, 
          lead(scale) over(partition by title order by scale asc) as next_scale,
          row_number() over(partition by title order by scale asc) as agg_row
       from signatures
       order by 3
 ) agg
where agg_row = 1;