mysql> select extractvalue('<a><b>xxx</c></a>','/a/b');

+------------------------------------------+

| extractvalue('<a><b>xxx</c></a>','/a/b') |

+------------------------------------------+

| xxx                                      |

+------------------------------------------+

1 row in set (0.00 sec)

<charsets>   

  <charset name="utf8">

    <collation name="utf8_5624_5_bad" id="369" shift-after-method="expand">

      <rules>

      <reset>a-a4</reset><p>xxx04</a>

      <reset>a-aa5</reset><p>xxx05</a>

      <reset>a-aaa6</reset><p>xxx06</a>

      <reset>a-aaaa7</reset><p>xxx07</a>

      <reset>a-aaaaa8</reset><p>xxx08</a>

      <reset>a-aaaaaa9</reset><p>xxx09</a>

      <reset>a-aaaaaa10</reset><p>xxx10</a>

      </rules>

    </collation>

    <collation name="utf8_maxuserid_ci" id="2047" version="4.0.0">

      <rules>   

        <reset>a</reset>

        <s>b</s>

      </rules>

    </collation>

  </charset>

</charsets>