sql - 在SQL查询中从xml中提取数据

Question

我正在尝试查询 SQL 2008R2 数据库 Surveillance并提取 MacAddress此 XML 列的值 Settings在表中Hardware我对 SQL 查询是全新的，但学习得很快。任何建议将不胜感激。

<properties>
  <settings hwid="hardware">
    <setting typeid="DAF813F8-2E02-4AE5-9F0F-B0FB203D3CB6">
      <name>ProductID</name>
      <value>AxisP3301</value>
    </setting>
    <setting typeid="F9D27CE8-8FA9-4B91-8C85-3E80DE7EF0AB">
      <name>MacAddress</name>
      <value>00408CC3ABCF</value>
    </setting>
    <setting typeid="FC714851-E998-4738-A140-F4FF20E99DEB">
      <name>FirmwareVersion</name>
      <value>5.40.9.2</value>
    </setting>
    <setting typeid="F1DED00E-9614-475F-A6F7-BA29FCA8DE39">
      <name>SerialNumber</name>
      <value>00408CC3ABCF</value>
    </setting>
    <setting typeid="5BE128A3-BDEC-4FEE-8690-D575DF03E3EE">
      <name>Bandwidth</name>
      <value>Unlimited</value>
    </setting>
    <setting typeid="188A93DE-67D8-417E-BCFC-FF5B3F74434A">
      <name>AudioEncoding</name>
      <value>G711</value>
    </setting>
    <setting typeid="5ADCDA37-78B3-4AB9-93E5-966EDE722FA3">
      <name>AlertEventServerIP</name>
      <value />
    </setting>
    <setting typeid="922AAF32-821A-4E24-A646-72A4AE592364">
      <name>AlertEventServerPort</name>
      <value>0</value>
    </setting>
    <setting typeid="18BF9B14-D675-40A1-B57D-90A03272468A">
      <name>SmtpEventServerIP</name>
      <value />
    </setting>
    <setting typeid="5F614912-4C46-453E-9043-3BFC15321E56">
      <name>SmtpEventServerPort</name>
      <value>25</value>
    </setting>
    <setting typeid="9F739984-A2C0-4E09-AAB6-97F229E9F208">
      <name>InternalEventServerIP</name>
      <value>25</value>
    </setting>
    <setting typeid="59094737-81C6-4FC2-B748-0005C390A775">
      <name>AttachmentSavePath</name>
      <value />
    </setting>
    <setting typeid="AF8875BC-7B45-4EBC-92DC-4E3959810A2E">
      <name>InternalEventServerPort</name>
      <value />
    </setting>
    <setting typeid="2B22F067-7AA4-4486-A206-85CBE3BE3285">
      <name>HTTPSPort</name>
      <value>443</value>
    </setting>
    <setting typeid="DA6E7891-54FA-4902-8164-75A790C11F17">
      <name>HTTPSEnabled</name>
      <value>no</value>
    </setting>
  </settings>
</properties>

Answer 1

您可以使用函数value()并更正 XQuery 以获得您需要的结果:

SELECT Settings.value('(/properties/settings/setting[name="MacAddress"]/value/text())[1]', 'varchar(255)') as MacAddress 
FROM Hardware

在这里您可以找到 setting 元素，该元素的子元素 name 的值为 MacAddress，并获取其子元素 value 的文本。使用 value() 函数时，您需要提供数据类型，因此在本例中以 varchar(255) 形式提供。

这里是 SQL Fiddle 的链接