根據另一列的值將一列匯總為兩個不同的列

Question

我需要的只是“存儲”中的項目列表，但結果集應包括存儲和活動位置中該項目數量的總和。

這是一個數據集示例：

ID	物品	地點	數量
1個	項目A	貯存	4個
2個	項目A	積極的	9
3個	項目B	貯存	3個
4個	項目B	貯存	2個
5個	項目A	積極的	1個
6個	C項	盒裝	3個
7	項目D	積極的	1個
8個	項目D	貯存	1個

結果看起來像這樣：

物品	貯存	積極的
項目A	4個	10
項目B	5個	0
項目D	1個	1個

請注意，不應包含 ItemC，因為它不在有效位置。

到目前為止我嘗試過的是：

SELECT 
    ITEMDESC.A, 
    SUM(CASE WHEN LOCATION.A='Storage' THEN QTY.A ELSE 0 END), 
    SUM(CASE WHEN LOCATION.B='Active'  THEN QTY.B ELSE 0 END)
 FROM       
    ITEMS A, ITEMS B
 INNER JOIN     
    ITEMDESC.A = ITEMDESC.B
 WHERE      
 GROUP BY   
    ITEMDESC.A

但這會返回列出的所有項目。 當我添加類似“WHERE Location.B = 'Storage'”的內容時，它只會對存儲中的項目求和，所有活動位置項目均為 0。

Answer 1

使用WHERE子句只查看有問題的位置：

select
  item,
  sum(case when location = 'Storage' then qty else 0 end) as storage,
  sum(case when location = 'Active' then qty else 0 end) as active
from items
where location in ('Storage', 'Active')
group by item
order by item;

更新

您已在請求中更改所需的 output，並且只需要“存儲”中的項目。 為此，只需添加一個HAVING子句，例如：

select
  item,
  sum(case when location = 'Storage' then qty else 0 end) as storage,
  sum(case when location = 'Active' then qty else 0 end) as active
from items
where location in ('Storage', 'Active')
group by item
having sum(case when location = 'Storage' then qty else 0 end) > 0
order by item;

Answer 2

這應該會給你想要的結果。 其他答案包括不在“存儲”中的值

select 
  item,
  sum(case when location = 'Active' then qty else 0 end) as active_qty,
  sum(case when location = 'Storage' then qty else 0 end) as storage_qty
from *table*
where item in (select item from *table* where location = 'Storage')
group by item
order by item;

Answer 3

Select  item,
        SUM(Case When Location = 'Storage' THEN Qty else 0 END) AS Storage,
        SUM(Case When Location = 'Active' THEN Qty else 0 END) AS Active 
from table1 
where location in ('Storage','Active')
GROUP BY Item

http://sqlfiddle.com/#!9/7339b9a/8

Answer 4

您可以在子查詢中使用 WHERE 子句來識別感興趣的項目，然后在聚合之前使用 JOIN 來過濾行

SELECT 
    A.ITEMDESC, 
    SUM(CASE WHEN A.LOCATION='Storage' THEN A.QTY ELSE 0 END), 
    SUM(CASE WHEN A.LOCATION='Active'  THEN A.QTY ELSE 0 END)
 FROM       
    ITEMS A
 INNER JOIN
    (SELECT DISTINCT ITEMDESC FROM ITEMS WHERE LOCATION='Storage') B
 ON      
    A. ITEMDESC = B.ITEMDESC
 GROUP BY   
    A.ITEMDESC

或者您可以在聚合后使用 HAVING 子句過濾行

SELECT 
    ITEMDESC, 
    SUM(CASE WHEN LOCATION='Storage' THEN QTY ELSE 0 END), 
    SUM(CASE WHEN LOCATION='Active'  THEN QTY ELSE 0 END)
 FROM       
    ITEMS
 GROUP BY   
    ITEMDESC
 HAVING
    MAX(CASE WHEN LOCATION='Storage' THEN 1 ELSE 0 END) > 0