SQL

Question

我正在编写查询以按月汇总销售额。我的问题是我的查询只有 returns 个月的销售记录。例如，我正在查看 15 个月的范围。但是对于下面示例中的一个特定部分，15 个月中只有 3 个月有销售。

我希望显示 15 条记录，而其他记录的销售额为 0。我希望获得额外记录的原因是我想取标准差，删除记录会影响计算。

示例代码：

SELECT I.PartNumber as PartNumber,
YEAR(O.CreateDate) as CreateDateYear,
MONTH(O.CreateDate) as CreateDateMonth,
COUNT(*) as TotalDemand
FROM OrderDetails OD
INNER JOIN Orders O on O.Id = OD.OrderId
INNER JOIN Items I on I.Id = OD.ItemId
WHERE 
O.CreateDate >= '1-1-2016' 
AND O.CreateDate <= '3-31-2017'
AND I.PartNumber = '5144831-2'
GROUP BY I.PartNumber, YEAR(O.CreateDate) , MONTH(O.CreateDate);

样本电流输出：

Part # | Year | Month | Demand
5144831-2   2017    1   1
5144831-2   2017    2   3
5144831-2   2016    3   1

期望输出：

我想要一个额外的行，例如：

5144831-2   2016    11  0

显示 2016 年 11 月没有销售。

我确实有一个临时 table #_date_array2 可能 months/years，我想我需要帮助合并 LEFT JOIN。

Answer 1

假设您每个月都有 的销售额，最简单的解决方案是切换到条件聚合：

SELECT '5144831-2' as PartNumber,
       YEAR(O.CreateDate) as CreateDateYear,
       MONTH(O.CreateDate) as CreateDateMonth,
       SUM(CASE WHEN I.PartNumber = '5144831-2' THEN 1 ELSE 0 END) as TotalDemand
FROM OrderDetails OD INNER JOIN
     Orders O 
     ON O.Id = OD.OrderId INNER JOIN
     Items I 
     ON I.Id = OD.ItemId
WHERE O.CreateDate >= '2016-01-01' AND
      O.CreateDate <= '2017-03-31'
GROUP BY YEAR(O.CreateDate) , MONTH(O.CreateDate);

注意：这是解决问题的技巧。更强大的解决方案涉及生成日期和使用 LEFT JOIN（或类似功能）。但是，这通常是获得结果的最快方法。

Answer 2

根据您对其他帖子等的所有评论，您似乎有一个 table 具有您想要的日期范围并且您希望能够运行分析 multiple/all 的零件号。因此，主要问题是您需要在您的日期 table 和当时售出的零件号之间进行笛卡尔连接，以便在未售出时完成“0”。

;WITH cteMaxMinDates AS (
    SELECT
       MinDate = MIN(DATEFROMPARTS(CreateDateYear,CreateDateMonth,1))
       ,MaxDate = MAX(DATEFROMPARTS(CreateDateYear,CreateDateMonth,1))
    FROM
       #_date_array2
)

;WITH cteOrderDetails AS (
    SELECT
       d.CreateDateYear
       ,d.CreateDateMonth
       ,I.PartNumber
    FROM
       #_date_array2 d
       INNER JOIN Orders o
       ON d.CreateDateMonth = MONTH(o.CreateDate)
       AND d.CreateDateYear = YEAR(o.CreateDate)
       INNER JOIN OrderDetails od
       ON o.Id = od.OrderId
       INNER JOIN Items i
       ON od.ItemId = i.Id
       AND i.PartNumber = '5144831-2'
)

, cteDistinctParts AS (
    SELECT DISTINCT PartNumber
    FROM
       cteOrderDetails
)

SELECT
    d.CreateDateYear
    ,d.CreateDateMonth
    ,I.PartNumber
    ,COUNT(od.PartNumber) as TotalDemand
FROM
    #_date_array2 d
    CROSS JOIN cteDistinctParts p
    LEFT JOIN cteOrderDetails od
    ON d.CreateDateYear = od.CreateDateYear
    AND d.CreateDateMonth = od.CreateDateMonth
    AND p.PartNumber = od.PartNumber
GROUP BY
    d.CreateDateYear
    ,d.CreateDateMonth
    ,I.PartNumber

要获得所有零件号，只需删除 AND i.PartNumber = '5144831-2' 连接条件。

Answer 3

如果要使用left join，则不能直接与inner join一起使用。您可以在括号内进行内连接，然后在外进行左连接，以避免弄乱左连接的结果。试试这个：

SELECT Z.PartNumber as PartNumber,
YEAR(O.CreateDate) as CreateDateYear,
MONTH(O.CreateDate) as CreateDateMonth,
COUNT(Z.OrderId) as TotalDemand
FROM Orders O 
LEFT JOIN 
(
    SELECT OrderId, PartNumber
    FROM
    OrderDetails OD 
    INNER JOIN Items I ON I.Id = OD.ItemId
    AND I.PartNumber = '5144831-2'
) Z
ON O.Id = Z.OrderId 
AND O.CreateDate >= '1-1-2016' 
AND O.CreateDate <= '3-31-2017'
GROUP BY Z.PartNumber, YEAR(O.CreateDate) , MONTH(O.CreateDate);

要在没有订单的月份获得 0 计数，请避免使用 count(*) 并使用上面给出的 count(OrderId)。

注意 - 您必须确保订单 table 具有可用的所有月份和年份，即如果 Orders 中没有 CreateDate 值，例如 2016 年 11 月table（在联接中留下 table），输出也不会产生本月的条目。

编辑： 你能试试这个吗：

SELECT Z.PartNumber as PartNumber,
YEAR(O.CreateDate) as CreateDateYear,
MONTH(O.CreateDate) as CreateDateMonth,
COUNT(O.OrderId) as TotalDemand
FROM Orders O 
RIGHT JOIN 
(
    SELECT OrderId, PartNumber
    FROM
    OrderDetails OD 
    INNER JOIN Items I ON I.Id = OD.ItemId
    AND I.PartNumber = '5144831-2'
) Z
ON O.Id = Z.OrderId 
AND O.CreateDate >= '1-1-2016' 
AND O.CreateDate <= '3-31-2017'
GROUP BY Z.PartNumber, YEAR(O.CreateDate) , MONTH(O.CreateDate);

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