Postgres列值分配

Question

我爲我的團隊運行收入查詢，但我們與另一個團隊分攤收入。但是，當我在Postgress中運行查詢時，我不知道如何分配列的價值，以致於我不能獲得我應該與另外3個其他團隊分攤的收入的100％ （我應該只計算收入的25％）。以下是我的查詢：

select to_char("Date", 'Mon/YYYY') as "Date", 
sum("Amount") FILTER (WHERE 
("Type" = 'C021') or --Shared with 3 other teams, only count 25% 
("Type" = 'C031') or --Shared with 3 other teams, only count 25% 
("Type" = 'C041') or --Shared with 3 other teams, only count 25% 
) 
as "Revenue", 
from "Transactions" 
where "Date" between '01/01/2015' and '12/31/2015' 
group by 1 
order by min("Date"); 

正如您所看到的，我從「Transactions」表中獲取數據。收入來自3個客戶，C021，C031和C041，並加在一起構成「收入」列。

但是，我想只計算每個客戶的25％，這樣一起添加的值僅佔每個客戶收入的25％。

Answer 1

假設還有其他類型的代碼需要100％的收入，您需要聯合而不是過濾器。

select to_char("Date", 'Mon/YYYY') as "Date", .25 * sum("Amount") as sub_total 
from "Transactions" 
where "Type" in ('C021', 'C031', 'C041') 
group by "Date" 
union 
-- 100% of revenue for all other type codes. Adjust for your 
-- actual situation. 
select to_char("Date", 'Mon/YYYY') as "Date", sum("Amount") 
from "Transactions" 
where "Type" not in ('C021', 'C031', 'C041') 
group by "Date" 

您可能需要調整第二個WHERE子句。

如果你只想要總數，這將每月返回一行。表達式to_char("Date", 'YYYY-mm')比較常見;它作爲一個字符串正確排序。

select "Date", sum(sub_total) as total 
from (select to_char("Date", 'YYYY-mm') as "Date", .25 * sum("Amount") as sub_total 
     from "Transactions" 
     where "Type" in ('C021', 'C031', 'C041') 
     group by "Date" 
     union 
     select to_char("Date", 'YYYY-mm') as "Date", sum("Amount") 
     from "Transactions" 
     where "Type" not in ('C021', 'C031', 'C041') 
     group by "Date") as subtotals 
group by "Date" 
order by "Date"