Sql 将多个数据集合并到一个查询中

我有多个疑问：

1)    select Year , Month, Sum(Stores) from ABC ;

2)     select Year, Month , Sum(SalesStores) from DEF ; 

3)     slect Year, Month, Sum(Products) from FGH;

我想要的结果是：

Year, Month , Sum(Stores), Sum(SalesStores), Sum(Products)

我尝试使用如下查询进行完全外部联接：

SELECT ISNULL(x.[Year], y.[Year]) AS [Year],
ISNULL(x.[Month], y.[Month]) AS [Month],
x.Sum_Stores,
y.Sum_SalesStores,
z.Sum_products
FROM (select Year , Month, Sum(Stores) AS Sum_Stores from ABC ... GROUP BY [Month]) AS x
FULL OUTER JOIN (select Year, Month , Sum(SalesStores) AS Sum_SalesStores from DEF ... GROUP BY [Month]) AS y
    ON x.[Year] = y.[Year] AND x.[Month] = y.[Month]
FULL OUTER JOIN (select Year, Month , Sum(products) AS Sum_products from FGH ... GROUP BY [Month])  AS z
ON y.[Year] = z.[Year] AND y.[Month] = z.[Month]

问题是，ABC只有特定月份的数据，DEF有不同月份的数据，而FGH又有不同月份的数据

当我运行上面的查询时，我得到很多空值和0

---

是否有人可以纠正我的问题，或者告诉我一个适合我的案例的解决方案。

使用union All和group by来代替：

   select x,y,z from tableA
   UNION
   select x,y,z from tableB
   UNION
   select x,y,z from tableC

    select year, month, sum(stores) as sumStores, sum(salesStores) as sumSalesStores, sum(products) as sumProducts
    from (
        select year, month, stores, salesStores = null, products = null
        from ABC

        union all

        select year, month, stores = null, salesStores, products = null
        from DEF

        union all

        select year, month, stores = null, salesStores = null, products
        from FGH
    ) x
    group by year, month;

---

使用以下方法可能更清晰：-

select 
    Year, 
    Month, 
    sum(Stores) as Stores, 
    sum(SalesStores) as SalesStores, 
    sum(products) as products
from (
    select Year, Month, Stores, 0.00 as SalesStores, 0.00 as products
    from ABC ...
    union all
    select Year, Month, 0 as Stores, SalesStores, 0 as products
    from DEF ...
    union all
    select Year, Month, 0 as Stores, 0 as SalesStores, products
    from FGH ...
) source
group by Year, Month

---

派生表中的第一个

select

语句定义了它的结构，您可能需要将该语句中的占位符列转换为正确精度和比例的类型，以允许后续

union

中的数据不丢失任何精度。

这里是获取此信息的另一种方法。此示例有一个简短的设置，用于演示此解决方案的实际效果

CREATE TABLE #ABC([Year] INT, [Month] INT, Stores INT);
CREATE TABLE #DEF([Year] INT, [Month] INT, SalesStores INT);
CREATE TABLE #GHI([Year] INT, [Month] INT, Products INT);

INSERT #ABC VALUES (2013,1,1);
INSERT #ABC VALUES (2013,1,2);
INSERT #ABC VALUES (2013,2,3);

INSERT #DEF VALUES (2013,1,4);
INSERT #DEF VALUES (2013,1,5);
INSERT #DEF VALUES (2013,2,6);

INSERT #GHI VALUES (2013,1,7);
INSERT #GHI VALUES (2013,1,8);
INSERT #GHI VALUES (2013,2,9);
INSERT #GHI VALUES (2013,3,10);


SELECT
     T.[Year]
    ,T.[Month]
    -- select the sum for each year/month combination using a correlated subquery (each result from the main query causes another data retrieval operation to be run)
    ,(SELECT SUM(Stores) FROM #ABC WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_Stores]
    ,(SELECT SUM(SalesStores) FROM #DEF WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_SalesStores]
    ,(SELECT SUM(Products) FROM #GHI WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_Products]
FROM (
    -- this selects a list of all possible dates.
    SELECT [Year],[Month] FROM #ABC
    UNION
    SELECT [Year],[Month] FROM #DEF
    UNION
    SELECT [Year],[Month] FROM #GHI
) AS T;

编辑： 可以根据请求将其封装在参数化存储过程中：

-- Call proc like this

--EXEC [getMyReport]; -- params are not required, these will default to NULL if not specified.
--EXEC [getMyReport] @Year=2013; -- all 2013 data, all months
--EXEC [getMyReport] @Month=1; -- all January data, from all years
--EXEC [getMyReport] @Year=2013, @Month=2; -- Feb 2013 data only.

CREATE PROCEDURE [dbo].[getMyReport]
     @Year INT = NULL -- default to NULL, this makes the param optional when you exec the procedure.
    ,@Month INT = NULL
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    SELECT
         T.[Year]
        ,T.[Month]
        -- select the sum for each year/month combination using a correlated subquery (each result from the main query causes another data retrieval operation to be run)
        ,(SELECT SUM(Stores) FROM #ABC WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_Stores]
        ,(SELECT SUM(SalesStores) FROM #DEF WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_SalesStores]
        ,(SELECT SUM(Products) FROM #GHI WHERE [Year]=T.[Year] AND [Month]=T.[Month]) AS [Sum_Products]
    FROM (
        -- this selects a list of all possible dates.
        SELECT [Year],[Month] FROM #ABC
        UNION
        SELECT [Year],[Month] FROM #DEF
        UNION
        SELECT [Year],[Month] FROM #GHI
    ) AS T
    WHERE
        -- if the param IS NULL, then it will not apply filtering
        -- if the param is specified, then it will filter by year or month
        (@Year IS NULL OR T.[Year]=@Year)
        AND
        (@Month IS NULL OR T.[Month]=@Month)
    ;
END
GO

---

以下是使用完全联接的答案：

select
     coalesce(ABC.Year,DEF.Year,FGH.Year) as Year
    ,coalesce(ABC.Month,DEF.Month,FGH.Month) as Month
    ,ABC.Stores
    ,DEF.SalesStores
    ,FGH.Products
from (
    select Year , Month, Sum(Stores) as Stores from ABC group by Year , Month
) ABC
full join (
    select Year, Month , Sum(SalesStores) as SalesStores from DEF group by Year , Month
) DEF
    on DEF.year = ABC.Year
    and DEF.Month = ABC.Month
full join (
    select Year, Month, Sum(Products) as Products from FGH group by Year , Month
) FGH
    on (FGH.year = ABC.Year
    and FGH.Month = ABC.Month)
    or (FGH.Month = DEF.Year
    and FGH.Month = DEF.Month)

---

您可以像这样合并多个集合：

SELECT Year, Month, 'Stores' AS Src, Stores AS Value FROM ABC
UNION ALL
SELECT Year, Month, 'SalesStores',   SalesStores     FROM DEF
UNION ALL
SELECT Year, Month, 'Products',      Products        FROM FGH

然后，使用聚合对它们进行排序：

SELECT
  Year,
  Month,
  Stores,
  SalesStores,
  Products
FROM (
  SELECT Year, Month, 'Stores',      Stores      FROM ABC
  UNION ALL
  SELECT Year, Month, 'SalesStores', SalesStores FROM DEF
  UNION ALL
  SELECT Year, Month, 'Products',    Products    FROM FGH
) AS s (Year, Month, Src, Value)
PIVOT (
  SUM(Value) FOR Src IN (Stores, SalesStores, Products)
) AS p
;

或者，首先聚合结果，然后合并聚合集，然后透视，可能更有效：

SELECT
  Year,
  Month,
  Stores,
  SalesStores,
  Products
FROM (
  SELECT Year, Month, 'Stores',      SUM(Stores)      FROM ABC
  UNION ALL
  SELECT Year, Month, 'SalesStores', SUM(SalesStores) FROM DEF
  UNION ALL
  SELECT Year, Month, 'Products',    SUM(Products)    FROM FGH
) AS s (Year, Month, Src, Value)
PIVOT (
  MAX(Value) FOR Src IN (Stores, SalesStores, Products)
) AS p
;

---

由于PIVOT语法要求使用聚合函数，因此我们可以使用一个只保留已聚合值的函数（在本例中为MAX）。

您的代码不包含

UNION

。感谢您的更正，DEF中的完整外部联接

选择年、月、和（SalesStores）不应执行。您是否缺少分组依据？我在原始查询中确实有分组依据。我想我会简化它，并且没有添加“按月分组”您的完全加入查询就在不远处了。我没有看到已经有了答案，所以我添加了一个工作示例供您参考。注意第三个表的join子句中的
coalesce
而不是
isnull
和
或
。嘿，谢谢，我有两个独立的列Year&Month，而不是date（MyDate）。。你能告诉我我需要如何修改你的查询才能在我的情况下工作吗？修改后的答案使用年和月作为独立的整型字段。太好了！！有没有办法让我通过一个月又一年的辩论，直到那个月才看到结果？？现在它显示一年中所有月份的数据+1并标记为答案。很好，如果性能很重要，您可能想尝试我的版本，因为它只会在表中出现一次，它可能会运行得稍微快一点。