sql - 在 SQL 中从 XML 中选择值

Question

我需要从 XML 文档中选择值。这些值存储为子节点，如下所示:

   <customers>
        <customer>
            <kunnr>1</kunnr>
            <kdgrp>2</kdgrp>
        </customer>
        <customer>
            <kunnr>2</kunnr>
            <kdgrp>2</kdgrp>
        </customer>
    </customers>

我需要为每个客户节点选择 kunnr 和 kdgrp 的值。我希望得到这样的结果:

kunnr       kdgrp
1           2
2           2

到目前为止我尝试了什么:

SELECT  @xml.query('/customers/customer/kunnr') AS KUNNR,
        @xml.query('/customers/customer/kdgrp') AS KDGRP

这会导致一行和两列包含 XML:

KUNNR                                     KDGRP
<kunnr>1</kunnr><kunnr>2</kunnr>          <kdgrp>2</kdgrp><kdgrp>2</kdgrp>

另一个尝试:

SELECT  C.value('/kunnr/text()','nvarchar(10)') as KUNNR,
        C.value('/kdgrp/text()','nvarchar(10)') as KDGRP
from @xml.nodes('/customers/customer') AS T(C);

这导致了以下错误消息:

XQuery [value()]: 'value()' requires a singleton (or empty sequence), found operand of type 'xdt:untypedAtomic *'

Answer 1

也许是这样的:

DECLARE @xml XML
SET @xml='<customers>
        <customer>
            <kunnr>1</kunnr>
            <kdgrp>2</kdgrp>
        </customer>
        <customer>
            <kunnr>2</kunnr>
            <kdgrp>2</kdgrp>
        </customer>
    </customers>'

然后是这样的查询:

SELECT
    c.value('kunnr[1]', 'nvarchar(10)') AS kunnr,
    c.value('kdgrp[1]', 'nvarchar(10)') AS kdgrp
FROM
    @xml.nodes('//customers/customer') as t(c)

这会给你这个结果:

kunnr  kdgrp
1      2
2      2