Grouping Set 中的列在不应该为 NULL 时为 NULL = SQL 服务器错误，或者更可能的是，我不了解 Grouping Sets 吗？

Question

我正在运行在 SQL Server 2019 Developer Edition 上编写下面的脚本。您可以运行在您自己的 SQL 服务器上，任何数据库都可以（不需要特定架构）。

在我的脚本底部，我有一个在 GROUP BY 子句中包含 2 个分组集的查询。第二个分组集包含一个表达式作为分组集中的唯一列，我在 SELECT 子句中输出相同的表达式作为名为 'Month' 的列。作为此分组集的结果呈现的行将此月份列输出为 NULL。

我不希望这样。我预计任何输出与分组集中指定的列相同的列都应该包含该组的行分组所依据的值。简而言之，我的结果集中的每一行都应该在月份列中有一个值，因为该列的表达式在我的两个分组集中。

我是不是想错了？通过运行ning 这个脚本在你的 SQL 服务器上尝试...

查询：

IF OBJECT_ID('tempdb..#InventoryItemBatch') IS NOT NULL
    DROP TABLE #InventoryItemBatch
CREATE TABLE #InventoryItemBatch
(
    [Id] [bigint] IDENTITY(1,1) NOT NULL,
    [Quantity] [int] NOT NULL,
    [BatchNumber] [varchar](200) NULL,
    [InventoryDate] [date] NOT NULL,
    [QuantityRemoved] [int] NOT NULL,
    [QuantityRemaining]  AS ([Quantity]-[QuantityRemoved]),
    [PricePerUnit] [decimal](18, 2) NULL,
)

SET NOCOUNT ON
SET IDENTITY_INSERT #InventoryItemBatch ON

MERGE INTO #InventoryItemBatch AS Target
USING (VALUES
  (144,543,'Q','1980-11-17',543,751.24)
 ,(1274,1,'S1','1980-08-17',0,0.00)
 ,(1469,609,'QA','1980-06-27',609,778.05)
 ,(1470,95,'QC','1980-11-24',95,887.99)
 ,(1473,120,'QB','1980-11-14',120,867.20)
 ,(1475,231,'QE','1980-05-15',231,783.09)
 ,(1476,109,'Q','1980-04-10',109,778.05)
 ,(1552,1,'S1','1980-05-28',0,3465.00)
 ,(3082,1,'S1','1980-05-30',0,20020.00)
 ,(4396,1,'S1','1980-05-31',0,3465.00)
 ,(4702,1,'S1','1980-08-17',0,0.00)
 ,(5114,1,'S1','1980-08-17',0,0.00)
 ,(5337,1,'S1','1978-04-07',0,1250.00)
 ,(5549,1,'S1','1980-08-17',0,0.00)
 ,(6152,1,'S1','1980-08-17',0,0.00)
 ,(6233,1,'S1','1980-07-22',0,0.00)
 ,(7616,1,'S1','1980-08-17',0,0.00)
 ,(9444,1,'S1','1980-04-30',0,3465.00)
 ,(10821,1,'S1','1980-05-21',0,1480.00)
 ,(11299,1,'S1','1980-09-14',0,1700.00)
 ,(17432,1,'S1','1980-02-18',0,1222.00)
 ,(20492,1,'S1','1980-02-12',0,2040.00)
 ,(22588,1,'S1','1980-01-01',0,0.00)
 ,(26842,1,'S1','1980-04-30',0,1593.00)
 ,(34323,1,'S1','1980-03-27',0,1219.00)
 ,(34334,1,'S1','1980-05-31',0,1219.00)
 ,(35223,1,'S1','1980-01-01',0,0.00)
 ,(35379,1,'S1','1980-02-18',0,1222.00)
 ,(36384,1,'S1','1980-04-30',0,3465.00)
 ,(36395,1,'S1','1980-07-13',0,1219.00)
 ,(43278,1,'S1','1978-06-09',0,850.00)
 ,(43998,1,'S1','1978-08-18',0,935.00)
 ,(47460,1,'S1','1978-03-15',0,2276.00)
 ,(47944,1,'S1','1978-04-07',0,0.00)
 ,(48926,1,'S1','1978-09-28',0,1350.00)
 ,(49166,1,'S1','1978-05-12',0,1602.00)
 ,(49248,1,'S1','1978-09-28',0,0.00)
 ,(49300,1,'S1','1978-05-12',0,0.00)
 ,(57492,1,'S1','1978-06-09',0,850.00)
 ,(57499,1,'S1','1979-06-30',0,963.00)
 ,(57524,1,'S1','1980-03-03',0,0.00)
) AS Source ([Id],[Quantity],[BatchNumber],[InventoryDate],[QuantityRemoved],[PricePerUnit])
ON (Target.[Id] = Source.[Id])
WHEN NOT MATCHED BY TARGET THEN
 INSERT([Id],[Quantity],[BatchNumber],[InventoryDate],[QuantityRemoved],[PricePerUnit])
 VALUES(Source.[Id],Source.[Quantity],Source.[BatchNumber],Source.[InventoryDate],Source.[QuantityRemoved],Source.[PricePerUnit])
;

SET IDENTITY_INSERT #InventoryItemBatch  OFF
SET NOCOUNT OFF


-- offending query
SELECT
    'Grouping-Month' = GROUPING(CONVERT(VARCHAR,YEAR(iib.InventoryDate)) + '.' + CONVERT(VARCHAR,FORMAT(iib.InventoryDate, 'MM')))
    , 'Grouping-Id' = GROUPING(iib.Id)
    , 'Grouping-DatePurchased' = GROUPING(iib.InventoryDate)

      -- this column should have a value in *eveny* row but is missing values for rows produced by the second grouping set
    , [Month] = CONVERT(VARCHAR,YEAR(iib.InventoryDate)) + '.' + CONVERT(VARCHAR,FORMAT(iib.InventoryDate, 'MM'))

    , Id = iib.Id
    , DatePurchased = iib.InventoryDate
    , SumPurchaseAmt = Sum(iib.PricePerUnit * iib.Quantity)

FROM #InventoryItemBatch iib
GROUP BY
    GROUPING SETS (
        (
            CONVERT(VARCHAR,YEAR(iib.InventoryDate)) + '.' + CONVERT(VARCHAR,FORMAT(iib.InventoryDate, 'MM'))
            , iib.Id
            , iib.InventoryDate
        )
        , (
            -- this is the grouping expression that I'm not seeing a value for
            CONVERT(VARCHAR,YEAR(iib.InventoryDate)) + '.' + CONVERT(VARCHAR,FORMAT(iib.InventoryDate, 'MM'))
        )
    )

部分输出：

附加信息：

我还注意到，如果您从 first 分组集中删除“iib.InventoryDate”列（并且还将其从 SELECT 子句中删除)，它实际上 修复了 我在这里提到的问题...... second 分组集输出的行现在确实包含那些Month 列中的缺失值。诡异的！！（对吗？）

这对我来说就像是一个错误。我是不是误会了？

Answer 1

重写查询以便显式引入 [Month]

with cte as (
    select  [Id] ,
    [Quantity] ,
    [BatchNumber] ,
    [InventoryDate] ,
    [QuantityRemoved] ,
    [QuantityRemaining] ,
    [PricePerUnit],
    [Month] = CONVERT(VARCHAR,YEAR(InventoryDate)) + '.' + CONVERT(VARCHAR,FORMAT(InventoryDate, 'MM'))
    from #InventoryItemBatch     
)

-- offending query
SELECT
    'Grouping-Month' = GROUPING([Month])
    , 'Grouping-Id' = GROUPING(iib.Id)
    , 'Grouping-DatePurchased' = GROUPING(iib.InventoryDate)
    , [Month]
    , Id = iib.Id
    , DatePurchased = InventoryDate
    , SumPurchaseAmt = Sum(iib.PricePerUnit * iib.Quantity)

FROM cte iib
GROUP BY
    GROUPING SETS (
        (
              iib.Id
            , iib.InventoryDate
            , [Month]   
        )
        , (
              [Month]
        )
    );

Grouping Set 中的列在不应该为 NULL 时为 NULL = SQL 服务器错误，或者更可能的是，我不了解 Grouping Sets 吗？

A column in a Grouping Set is NULL when it shouldn't be = SQL Server bug, or more likely, do I not understand Grouping Sets?

sql

sql-server

grouping-sets