Question

我有以下SQL：

select  distinct cat, sum(cnt)
from
(
select distinct prcIncidentManagement.CallCategory cat, count(eFolder.eFolderName) cnt
from prcIncidentManagement
inner join eFolder
on prcIncidentManagement.EFOLDERID=eFolder.eFolderID
group by prcIncidentManagement.CallCategory

union all

select distinct prcRequestFulfilment.CallCategory cat, count(eFolder.eFolderName) cnt
from prcRequestFulfilment
inner join eFolder
on prcRequestFulfilment.EFOLDERID=eFolder.eFolderID
group by prcRequestFulfilment.CallCategory
) results
order by 1

我发现很难对总数进行求和并将其与呼叫类别进行分组，因为错误消息如下：

列'results.cat'在选择列表中无效，因为它不是包含在聚合函数或GROUP BY子句
中

无论如何？

Answer 1

删除distinct并在外部查询中添加GROUP BY：

select  cat, sum(cnt)
from
(
    select prcIncidentManagement.CallCategory cat, count(eFolder.eFolderName) cnt
    from prcIncidentManagement
    inner join eFolder
    on prcIncidentManagement.EFOLDERID=eFolder.eFolderID
    group by prcIncidentManagement.CallCategory
    union all
    select prcRequestFulfilment.CallCategory cat, count(eFolder.eFolderName) cnt
    from prcRequestFulfilment
    inner join eFolder
    on prcRequestFulfilment.EFOLDERID=eFolder.eFolderID
    group by prcRequestFulfilment.CallCategory
) results
GROUP BY cat
order by 1;

添加和聚合函数时，可以选择不在group by子句中或聚合函数中的额外列。

此外，子查询中不需要DISTINCT具有聚合函数，因为它是无用的，因为group by将为您提供具有聚合函数的不同列，以聚合每个列的其他列小组，所以你不需要它。

Answer 2

如果我假设eFolderName永远不会NULL且eFolderId具有正确的外键关系（这两者都是非常合理的假设），那么您可以通过删除基础来简化查询加入子查询：

select cat, sum(cnt)
from ((select im.CallCategory as cat, count(im.eFolderID) as cnt
       from prcIncidentManagement im
       group by im.CallCategory
      ) union all
      (select f.CallCategory as cat, count(im.eFolderID) as cnt
       from prcRequestFulfilment f
       group by f.CallCategory
      ) 
     ) results
group by cat
order by cat;

sql union sum与不同的描述字段

2 个答案: