SQL

Question

我有 table 看起来像这样：

+----+------+--------+--------+--------+-------+
| ID | AcID | TypeID | Value1 | Value2 | Notes |
+----+------+--------+--------+--------+-------+
| 1  | 33   | 1      | Hash1  | Dash1  |       |
| 2  | 33   | 2      | Hash2  | Dash2  |       |
| 3  | 33   | 3      | Hash3  | Dash3  |       |
| 4  | 33   | 4      | Hash4  | Dash4  | lala  |
+----+------+--------+--------+--------+-------+

在 select 之后，我希望得到如下所示的结果：

+------+---------+---------+---------+---------+---------------+
| AcID | TypeID1 | TypeID2 | TypeID3 | TypeID4 | TypeID4_Notes |
+------+---------+---------+---------+---------+---------------+
| 33   | Hash1   | Hash2   | Hash3   | Dash4   |     lala      |
+------+---------+---------+---------+---------+---------------+

使用 Pivot 我可以获得：

SELECT [1], [2], [3], [4]
FROM SourceTable
PIVOT
(
MAX(value1)
FOR typeID IN ( [1], [2], [3], [4])
) AS PivotTable

结果：

+-------+-------+-------+-------+
| Type1 | Type2 | Type3 | Type4 |
+-------+-------+-------+-------+
| hash1 | Hash2 | Hash3 | Hash4 |
+-------+-------+-------+-------+

我如何将 actID 添加到结果 + 将 type4 值更改为 Dash4 并添加名为 Notes 的列，其中包含 type4 注释的值。 Header 名称无关紧要，只需要将所需的数据字段放入结果中即可。

谢谢

解决方法：完成查询 ->

SELECT * FROM   (SELECT AcID,
               CASE
                 WHEN cname = 'Notes' THEN 'typeID' + CONVERT(VARCHAR(15), typeID) + '_' + cname
                 ELSE cname + CONVERT(VARCHAR(15), typeID)
               END AS typeid,
               data
        FROM   (SELECT id,
                       AcID,
                       typeID,
                       CASE
                         WHEN typeID <> 4 THEN Value1
                         ELSE Value2
                       END AS typeids,
                       Notes
                FROM   mytable) a
               CROSS apply (VALUES ('typeid',CONVERT(VARCHAR(150),typeids)),
                                   ('Notes',notes)) cs(cname, data)) b
       PIVOT (Max(data)
             FOR typeid IN ([typeid1],[typeid2],[typeid3],[typeid4],
                            [typeid4_Notes] )) pv

现在还有一个问题 -> 为什么我必须将 typeids 转换为字符串值？（最初在数据库中它们是日期时间，但是当我不转换时它会抛出错误）@NoDisplayName

Answer 1

因为你想旋转两列 value 和 notes 我建议你首先使用 cross apply

将两列转换为单列

然后旋转该列以获得结果。

SELECT *
FROM   (SELECT AcID,
               CASE
                 WHEN cname = 'notes' THEN 'typeid' + CONVERT(VARCHAR(15), id) + '_' + cname
                 ELSE cname + CONVERT(VARCHAR(15), id)
               END AS typeid,
               data
        FROM   (SELECT id,
                       AcID,
                       CASE
                         WHEN notes <> '' THEN Value1
                         ELSE Value2
                       END AS typeids,
                       Notes
                FROM   Yourtable) a
               CROSS apply (VALUES ('typeid',typeids),
                                   ('Notes',notes)) cs(cname, data)) b
       PIVOT (Max(data)
             FOR typeid IN ([typeid1],[typeid2],[typeid3],[typeid4],
                            [typeid4_Notes] )) pv

SQL - 按一列分组，但 select 来自不同行的多列作为列

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