SQL在外部查询中添加一个过滤器以应用于所有子查询

Question

我正在创建一个包含多个子查询的查询，这些子查询以不同的状态/类别/等显示事件数量。 日期过滤器将需要应用于所有子查询，以便计算在日期范围内创建的事件数。

由于报表将被移至Business Objects，因此我无法在子查询中多次指定日期。 因此，我将子查询中的事件表（inc）与外部查询中的另一个事件表（inc_filter）联接在一起，并希望将一个日期过滤器应用于所有子查询。

但是返回的结果不正确，我得到了多个行，这些行的值为0或1。

有人能指出我正确的方向吗？

SELECT 
(SELECT COUNT(*)
FROM Incident inc
WHERE  inc.id = inc_filter.id
                 AND inc.status = 'Open')
            "Total # of Open Inc",
(SELECT COUNT(*) 
FROM Incident inc
WHERE  inc.id = inc_filter.id
                 AND inc.status = 'Closed')
            "Total # of Closed Inc"
--more sub-queries here...

FROM Incident inc_filter
AND inc_filter.CREATED > '10-Apr-2017'
AND inc_filter.CREATED < '13-Apr-2017'

Answer 1

您可能只是在寻找条件聚合：

SELECT 
  COUNT(CASE WHEN status = 'Open' THEN 1 END) AS "Total # of Open Inc",
  COUNT(CASE WHEN status = 'Closed' THEN 1 END) AS "Total # of Closed Inc"
-- more counts here...
FROM Incident 
WHERE created >= DATE '2017-04-10' AND created < DATE '2017-04-13';

Answer 2

首先，您应该使用用case ，而不需要使用许多子查询，第二，如果我理解您的问题，则应使用sum()这样

SELECT sum(case when inc_filter.status = 'Open' then 1 else 0 end) as open,
sum(case when inc_filter.status = 'Closed' then 1 else 0 end) as closed

FROM Incident inc_filter
AND inc_filter.CREATED > '10-Apr-2017'
AND inc_filter.CREATED < '13-Apr-2017'

Answer 3

亲爱的，您需要在您的总和之上，再进行一次选择。 实际上，您正在使用组功能，但这适用于行级别。 您需要对所有子查询列求和以查看所需结果，例如您的查询将是

select sum("Total # of Open Inc") ,sum("Total # of Closed Inc")
from(
SELECT 
(SELECT COUNT(*)
FROM Incident inc
WHERE  inc.id = inc_filter.id
                 AND inc.status = 'Open')
            "Total # of Open Inc",
(SELECT COUNT(*) 
FROM Incident inc
WHERE  inc.id = inc_filter.id
                 AND inc.status = 'Closed')
            "Total # of Closed Inc"
--more sub-queries here...

FROM Incident inc_filter
AND inc_filter.CREATED > '10-Apr-2017'
AND inc_filter.CREATED < '13-Apr-2017');

但是最好使用联接