汇总 SQL Server XML 列中特定节点的所有实例答案

【问题标题】：Sum all instances of a particular node in a SQL Server XML column汇总 SQL Server XML 列中特定节点的所有实例
【发布时间】：2019-06-10 19:42:24
【问题描述】：

我有以下 xml 数据列：

<AccountingDetail>
    <DetailItems>
        <AccountingDetailItem>
            <Credit>25</Credit>
            <Debit>15100</Debit>
        </AccountingDetailItem>
        <AccountingDetailItem>
            <Credit>5</Credit>
            <Debit>150.66</Debit>
        </AccountingDetailItem>
    </DetailItems>
</AccountingDetail>

如何获得此列中所有贷方和借方的总和？实例的数量因行而异。

我希望 sum(debits) = 15250.66 & sum(credits) = 30

【问题讨论】：

标签： sql-server xml xml-parsing

【解决方案1】：

您可以使用 CTE（通用表表达式）轻松完成此操作 - 类似这样（假设我们的 XML 数据存储在 @XmlData XML 变量中）：

-- define the CTE to extract the individual Credit and Debit values
;WITH RawXmlData (Credit, Debit) AS
(
    SELECT
        Credit = ISNULL(XC.value('(Credit)[1]', 'decimal(16,4)'), 0.0),
        Debit = ISNULL(XC.value('(Debit)[1]', 'decimal(16,4)'), 0.0)
    FROM
        @XmlData.nodes('/AccountingDetail/DetailItems/AccountingDetailItem') XT(XC)
)
-- now select from that CTE and sum up the values
SELECT
    SumCredit = SUM(Credit),
    SumDebit = SUM(Debit)
FROM
    RawXmlData

【讨论】：

【解决方案2】：

这可以在 XML/XQuery 中解决，它应该比创建派生集并在外部进行聚合更好：

DECLARE @tbl TABLE(ID INT IDENTITY,YourXml XML);
INSERT INTO @tbl VALUES
(N'<AccountingDetail>
    <DetailItems>
        <AccountingDetailItem>
            <Credit>25</Credit>
            <Debit>15100</Debit>
        </AccountingDetailItem>
        <AccountingDetailItem>
            <Credit>5</Credit>
            <Debit>150.66</Debit>
        </AccountingDetailItem>
    </DetailItems>
</AccountingDetail>')
,('<AccountingDetail>
    <DetailItems>
        <AccountingDetailItem>
            <Credit>10</Credit>
            <Debit>20</Debit>
        </AccountingDetailItem>
        <AccountingDetailItem>
            <Credit>20</Credit>
            <Debit>40</Debit>
        </AccountingDetailItem>
        <AccountingDetailItem>
            <Credit>30</Credit>
            <Debit>60</Debit>
        </AccountingDetailItem>
    </DetailItems>
</AccountingDetail>');

SELECT t.YourXml.value('sum(//Credit)','decimal(16,4)') AS SumCredit
      ,t.YourXml.value('sum(//Debit)','decimal(16,4)') AS SumDebit
FROM @tbl t;

【讨论】：