將多個結果合並為列而不是行

Question

我需要對數據庫中的各個表進行大量計數
我想將這些計數合並為一個結果。

考慮以下查詢：

SELECT 100 As SomeCount
SELECT 200 As SomeOtherCount
SELECT 300 As YetAnotherCount

如果我使用UNION合並它們，則每個結果將在最終結果中排成一行：

SELECT 100 As SomeCount
UNION
SELECT 200 As SomeOtherCount
UNION
SELECT 300 As YetAnotherCount

輸出：

> SomeCount
> --------- 
> 100 
> 200 
> 300

我想要的是

> SomeCount | SomeOtherCount | YetAnotherCount
> --------------------------------------------
>   100     |      200       |     300

我可以想到的“命名”結果的唯一其他方法是使用類似以下內容的方法：

SELECT 'SomeCount' As Name, 100 As Value
UNION ALL
SELECT 'SomeOtherCount', 200
UNION ALL
SELECT 'YetAnotherCount', 300

在這種情況下，結果如下所示：

>     Name          |      Value
> ---------------------------------
> 'SomeCount'       |       100
> 'SomeOtherCount'  |       200
> 'YetAnotherCount' |       300

有沒有一種方法可以得到我想要的結果，還是最后一種方法呢？

我應該提到上面的查詢非常簡單，以解釋核心問題。 實際上，需要組合的兩個查詢可能看起來像這樣：

查詢1：

SELECT Count(Id) As UndeliveredSms
FROM
(
 SELECT Id
 FROM IncomingSms
 WHERE Id NOT IN (SELECT IncomingSmsId
                  FROM DeliveryAttempt
                  WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
 )

查詢2：

SELECT Count(Id) As UndeliveredEMail FROM
(
 SELECT Id
 FROM IncomingEMail
 WHERE Id NOT IN (SELECT IncomingEMailId
                  FROM DeliveryAttempt
                  WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
)

將它們包裝在另一個SELECT語句中不適用於SQlite。

使用示例中的最后一種方法確實可行，除非有壞主意，否則我可以選擇該解決方案：

SELECT 'UndeliveredSms' As Name,  Count(Id) As Value
FROM
(
 SELECT Id
 FROM IncomingSms
 WHERE Id NOT IN (SELECT IncomingSmsId
                  FROM DeliveryAttempt
                  WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
 )

UNION

SELECT 'UndeliveredEMail', Count(Id) FROM
(
 SELECT Id
 FROM IncomingEMail
 WHERE Id NOT IN (SELECT IncomingEMailId
                  FROM DeliveryAttempt
                  WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
)

結果是這樣的：

>     Name           |     Value
> ---------------------------------
> UndeliveredEMail   |       82
> UndeliveredSms     |       0

當然，實際上，還有很多事情要數

Answer 1

您應該能夠在查詢之間使用CROSS JOIN：

SELECT *
FROM
(
  SELECT Count(Id) As UndeliveredSms
  FROM
  (
   SELECT Id
   FROM IncomingSms
   WHERE Id NOT IN (SELECT IncomingSmsId
                    FROM DeliveryAttempt
                    WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
  )
)
CROSS JOIN
(
  SELECT Count(Id) As UndeliveredEMail FROM
  (
   SELECT Id
   FROM IncomingEMail
   WHERE Id NOT IN (SELECT IncomingEMailId
                    FROM DeliveryAttempt
                    WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
  )
);

參見帶有演示的SQL Fiddle

Answer 2

我不理解在您的查詢中使用UNION ，但也許我誤會了。 不在子集中並集不是全部=不在子集中...

似乎可以簡化為以下內容：

select *
from
(
  SELECT Count(Id) As UndeliveredSms
  FROM IncomingSms
  WHERE Id NOT IN (SELECT IncomingSmsId
                    FROM DeliveryAttempt
                    WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
) t, 
(
  SELECT Count(Id) As UndeliveredEMail 
  FROM IncomingEMail
  WHERE Id NOT IN (SELECT IncomingEMailId
                    FROM DeliveryAttempt
                    WHERE Status = 'Delivered' OR Status = 'FailedPermanently')
  ) t2