Unpivot 多列未显示期望结果

Question

Original
    RecordKey   Name Section1_Product   Section1_Code   Section2_Product   Section2_Code ......
    1           a         ff              22               
    2           b         gg              22
    3           c         hh              33


    RecordKey     Name      Section     Product      Code ......
    1               a           1         ff          22
    1               a           2
    2               b           1         gg          22
    2               b           2
    3               c           1         hh          22
    3               c           2

我正在尝试将列还原为行。有些部分会有空值。

SELECT RecordKey
 ,Name
 ,'Num_of_Sections' = ROW_NUMBER() OVER (PARTITION BY RecordKey ORDER BY ID)
 ,Product
 ,Code
FROM (
SELECT RecordKey, Name, Section1_Product, Section1_Code, Section2_Product, Section2_Code FROM Table
) M

UNPITVOT (
  Product FOR ID IN (Section1_Product, Section2_Product)
) p

UNPIVOT (
  Code FOR CO IN (Section1_Code, Section2_Code)
) c

如果我只使用一列（产品，注释掉代码）执行，那么我将在 ID 列 (1,2) 中有 2 个值。如果我使用 2 列运行查询，那么我在 ID 列中得到 4 个值（1、2、3、4）。

Answer 1

可能根据我的假设和您提供的数据，我们可以使用 Cross apply 和 Row_number 实现这一目标

    declare @Record TABLE 
    ([RecordKey] int, 
    [Name] varchar(1), 
    [Section1_Product] varchar(2), 
    [Section1_Code] int, 
    [Section2_Product] varchar(2),
     [Section2_Code] int)
;

INSERT INTO @Record
    ([RecordKey], [Name], [Section1_Product], [Section1_Code],[Section2_Product],[Section2_Code])
VALUES
    (1, 'a', 'ff', 22,NULL,NULL),
    (2, 'b', 'gg', 22,NULL,NULL),
    (3, 'c', 'hh', 33,NULL,NULL)
;
    With cte as (
    Select T.RecordKey,
    T.Name,
    T.val,
    T.val1 from (
    select RecordKey,Name,val,val1 from @Record
    CROSS APPLY (VALUES
                ('Section1_Product',Section1_Product),
                ('Section2_Product',Section2_Product))cs(col,val)
    CROSS APPLY (VALUES
                ('Section1_Code',Section1_Code),
                ('Section2_Code',Section2_Code))css(col1,val1)
    WHERE val is NOT NULL)T
    )
Select  c.RecordKey,
        c.Name,
        c.RN,
        CASE WHEN RN = 2 THEN NULL ELSE c.val END Product,
        c.val1 Code 
            from (
Select RecordKey,
        Name,
        ROW_NUMBER()OVER(PARTITION BY val ORDER BY (SELECT NULL))RN,
        val,
        val1 from cte )C