xpath_boolean
xpath_boolean 介绍
xpath_boolean(xml, xpath) - 如果XPath表达式求值为真，或者找到了匹配的节点，则返回真。
Examples:
> SELECT xpath_boolean('<a><b>1</b></a>','a/b');
true
Since: 2.0.0
xpath_boolean(xml, xpath) - 如果XPath表达式求值为真，或者找到了匹配的节点，则返回真。
Examples:
> SELECT xpath_boolean('<a><b>1</b></a>','a/b');
true
Since: 2.0.0