将多个结果合并为列而不是行

Question

我需要对数据库中的各个表进行大量计数
我想将这些计数合并为一个结果。

考虑以下查询：

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

如果我使用UNION合并它们，则每个结果将在最终结果中排成一行：

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

输出：

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

我想要的是

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

我可以想到的“命名”结果的唯一其他方法是使用类似以下内容的方法：

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

在这种情况下，结果如下所示：

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

有没有一种方法可以得到我想要的结果，还是最后一种方法呢？

我应该提到上面的查询非常简单，以解释核心问题。 实际上，需要组合的两个查询可能看起来像这样：

查询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')
 )

查询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')
)

将它们包装在另一个SELECT语句中不适用于SQlite。

使用示例中的最后一种方法确实可行，除非有坏主意，否则我可以选择该解决方案：

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')
)

结果是这样的：

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

当然，实际上，还有很多事情要数

Answer 1

您应该能够在查询之间使用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')
  )
);

参见带有演示的SQL Fiddle

Answer 2

我不理解在您的查询中使用UNION ，但也许我误会了。 不在子集中并集不是全部=不在子集中...

似乎可以简化为以下内容：

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