1·我们希望将查询的范围限制在包含邮政编码为“79081”的客户的行。
We would like to limit the query to rows that contain a customer whose zip code is "79081".
2·这个 XPath 表达式可以解释为：返回邮政编码为 “79081” 的 address 元素的序列。
The XPath expression can be interpreted as: return a sequence of address elements whose zip is "79081".
3·在我们的示例中。 传递给 XMLEXISTS() 的 XQuery 表达式是一个简单的 XPath 表达式，其中的 $t 是 XML 列 data：$t/marketinfo/sales/customer/address[zip = "79081"]。
In our example, the XQuery expression that we pass to XMLEXISTS() is a simple XPath expression where $t is the XML column data: $t/marketinfo/sales/customer/address[zip = "79081"].