结合两个表的一个输出

Question

说我有两个表：

KnownHours：

ChargeNum    CategoryID    Month    Hours
111111       1             2/1/09   10
111111       1             3/1/09   30
111111       1             4/1/09   50
222222       1             3/1/09   40
111111       2             4/1/09   50

UnknownHours：

ChargeNum   Month   Hours
111111      2/1/09  70
111111      3/1/09  40.5
222222      7/1/09  25.5

我需要这些基团时，忽略月，成单个数据表，使得我的预期的结果如下：

ChargeNum    CategoryID     Hours
111111       1              90
111111       2              50
111111       Unknown        110.5
222222       1              40
222222       Unknown        25.5

我似乎无法算出这个。任何帮助将不胜感激！

编辑：我需要求和小时对于每个ChargeNum /类别组合。我的采样数据更新，以反映这一点。

Answer 1

您需要使用UNION的结果组合两个查询。在你的情况：

SELECT ChargeNum, CategoryID, SUM(Hours)
FROM KnownHours
GROUP BY ChargeNum, CategoryID
UNION ALL
SELECT ChargeNum, 'Unknown' AS CategoryID, SUM(Hours)
FROM UnknownHours
GROUP BY ChargeNum

请注意 - 如果使用UNION ALL在上面，它并不比单独运行这两个查询因为它没有重复检查慢

。

Answer 2

在您的预期产出，你已经得到了第二次最后一排总和不正确，应该根据你的表中的数据是40，但在这里是查询：

Select  ChargeNum, CategoryId, Sum(Hours)
From    (
    Select  ChargeNum, CategoryId, Hours
    From    KnownHours
    Union
    Select  ChargeNum, 'Unknown' As CategoryId, Hours
    From    UnknownHours
) As a
Group By ChargeNum, CategoryId
Order By ChargeNum, CategoryId

这里是输出：

ChargeNum  CategoryId 
---------- ---------- ----------------------
111111     1          40
111111     2          50
111111     Unknown    70
222222     1          40
222222     Unknown    25.5

Answer 3

我们可以借此一步越走越说合并时，是具有50小时以上我只是想看看行...我已经试过这一点，但得到一个错误，它无法找到SumHours ...

Select  ChargeNum, CategoryId, Sum(Hours) As SumHours
From    (
    Select  ChargeNum, CategoryId, Hours
    From    KnownHours
    Union
    Select  ChargeNum, 'Unknown' As CategoryId, Hours
    From    UnknownHours
) As a
WHERE (SumHours>=50)
Group By ChargeNum, CategoryId
Order By ChargeNum, CategoryId

所以，我试图

    Select  ChargeNum, CategoryId, Sum(Hours) As SumHours
From    (
    Select  ChargeNum, CategoryId, Hours
    From    KnownHours
    Union
    Select  ChargeNum, 'Unknown' As CategoryId, Hours
    From    UnknownHours
) As a
WHERE (Hours>=50)
Group By ChargeNum, CategoryId
Order By ChargeNum, CategoryId

但是，这是不给的时间的总和上两个表...