如何编写此 SQL Server 查询：在唯一行中添加值？

Question

我有一个如下查询。表之间的关系是：

每辆卡车可能有多个司机。表列表将表 Truck 中的每一行与表 Driver 中的行连接起来。现在我想获取特定条件下独特卡车的数量，以及该条件下独特卡车的总大小。

这是我所拥有的：

SELECT t.Year AS [Year]
        , t.Month AS [Month]
        , t.Day AS [Day]

        -- Count will not count NULL
        , COUNT( DISTINCT (CASE WHEN (t.Sent = 1 AND r.Internal=1) THEN L.TruckId
                ELSE NULL
            END) ) AS [Count]

        , SUM(CASE WHEN (t.Sent = 1 AND r.Internal = 1) THEN t.Size
            END) AS [Size]

FROM Truck t
INNER JOIN List L ON t.Id = L.TruckId
        INNER JOIN Driver r ON L.DriverId = r.Id
GROUP BY t.Year, t.Month, t.Day

• COUNT 正确，但 SUM 不正确。

我的问题是如何得到这个 SUM？ 而且我不想写 2 个查询并加入它们。

谢谢

Answer 1

您可以尝试如下查询：

; with cte as (
SELECT 
    DISTINCT
      t.Year AS [Year]
    , t.Month AS [Month]
    , t.Day AS [Day]
    , L.TruckId,
    , t.Size
FROM Truck t
INNER JOIN List L ON t.Id = L.TruckId
INNER JOIN Driver r ON L.DriverId = r.Id
WHERE t.Sent = 1 AND r.Internal=1
)
select 
      Year
    , Month
    , Day
    , count(TruckId) AS [Count]
    , sum(Size) AS [Size]
from cte 
group by Year, Month, Day