sql - 按子字符串动态透视列

Question

我有这张桌子：

itemid                  attributename   value
6829556334057807840       Part Notes    Drilling Required: No,Install Time: 30 Minutes,Fascia Trimming: Yes (minor),Visibility: Exposed

我希望能够将 Value 列中的数据转换为 KeyValue 对

Example:

    ItemId                  Key                  Value
6829556334057807840       Drilling Required       No
6829556334057807840       Install Time            30
6829556334057807840       Fascia Trimming         Yes (minor)

但是，数据透视必须是动态的，因为值列可以有多个不同的键值，具体取决于列中的内容。

Answer 1

考虑数据库的规范化。如果您有未知数据，请使用 xml（自 SQL Server 2005 起受支持）或 JSON（自 SQL Server 2016 起受支持）。使用此查询作为起点：

WITH Src AS
(
    SELECT * FROM (VALUES
        ('6829556334057807840', 'Part Notes', 'Drilling Required: No,Install Time: 30 Minutes,Fascia Trimming: Yes (minor),Visibility: Exposed')
    ) T(itemid, attributename, value)
), Recurse AS
(
    SELECT
        itemid,
        SUBSTRING(value, 1, CASE WHEN CHARINDEX(',', value, 1)=0 THEN LEN(value) ELSE CHARINDEX(',', value, 1)-1 END) Item,
        SUBSTRING(value, CASE WHEN CHARINDEX(',', value, 1)=0 THEN LEN(value) ELSE CHARINDEX(',', value, 1)+1 END, LEN(value)) Rest
    FROM Src
    UNION ALL
    SELECT
        itemid,
        CASE WHEN CHARINDEX(',', Rest, 1)=0 THEN Rest ELSE SUBSTRING(Rest, 1, CHARINDEX(',', Rest)-1) END Item,
        CASE WHEN CHARINDEX(',', Rest, 1)=0 THEN NULL ELSE SUBSTRING(Rest, CHARINDEX(',', Rest)+1, LEN(Rest)) END Rest
    FROM Recurse
    WHERE Rest IS NOT NULL
)
SELECT
    itemid,
    SUBSTRING(Item, 1, CHARINDEX(':', Item)-1) [Key],
    SUBSTRING(Item, CHARINDEX(':', Item)+1, LEN(Item)) [Value]
FROM Recurse

它返回：

itemid               Key                   Value
-------------------  --------------------  -------------
6829556334057807840  Drilling Required     No
6829556334057807840  Install Time          30 Minutes
6829556334057807840  Fascia Trimming       Yes (minor)
6829556334057807840  Visibility            Exposed

Answer 2

XML的另一种方式：

DECLARE @xml xml

SELECT @xml = (
    SELECT CAST('<item id="' + CAST(itemid as nvarchar(100)) +'"><row><key>' +
            REPLACE(REPLACE([value],',','</value></row><row><key>'),': ','</key><value>')+'</value></row></item>' as xml)
    FROM YourTable
    FOR XML PATH('')
)

SELECT  t.v.value('../@id','bigint') ItemId,                                    
        t.v.value('key[1]','nvarchar(max)') [Key],
        t.v.value('value[1]','nvarchar(max)') [Value]
FROM @xml.nodes('/item/row') as t(v)

对于您提供的表格样本，输出将是：

ItemId              Key                 Value
6829556334057807840 Drilling Required   No
6829556334057807840 Install Time        30 Minutes
6829556334057807840 Fascia Trimming     Yes (minor)
6829556334057807840 Visibility          Exposed

XML PATH这是使用和替换转换表后获得的 XML 数据：

<item id="6829556334057807840">
  <row>
    <key>Drilling Required</key>
    <value>No</value>
  </row>
  <row>
    <key>Install Time</key>
    <value>30 Minutes</value>
  </row>
  <row>
    <key>Fascia Trimming</key>
    <value>Yes (minor)</value>
  </row>
  <row>
    <key>Visibility</key>
    <value>Exposed</value>
  </row>
</item>