Xquery - 使用 XMLtable 从 XML 中选择值

Question

我想使用 XQuery 在以下 XML 中显示 FrequencyCdvalue="01" 和 city type="first" 的值。

你能帮帮我吗

<Envelope>
<Arrangement>
<FrequencyCd value="01">first first</FrequencyCd> 
<FrequencyCd value="02">first second</FrequencyCd> 
<contactinfo> <Address>
<street>234 Rolling Lane</street> 
<city type="first">Rockport</city> 
</Address>
<email>love2fish@finmail.com</email> 
</contactinfo>
</Arrangement>
<Arrangement>
<FrequencyCd value="03">second first</FrequencyCd> 
<FrequencyCd value="04">second second</FrequencyCd> 
<contactinfo>
<Address>
<street>234 Straight Lane</street> 
<city type="first">Crackport</city> 
</Address>
<email>hate2fish@finmail.com</email> 
</contactinfo>
</Arrangement>
</Envelope>

Answer 1

这种方法在内部分解更多行，但允许复合过滤条件（FrequencyCd 和 City 的条件）作为分解 XML 数据（XMLTABLE 函数的输出）的 SQL 表示的简单 WHERE 子句实现。

with origxml(xdoc) AS (VALUES XMLPARSE( DOCUMENT 
    '<Envelope>
    <Arrangement>
    <FrequencyCd value="01">first first</FrequencyCd> 
    <FrequencyCd value="02">first second</FrequencyCd> 
    <contactinfo> <Address>
    <street>234 Rolling Lane</street> 
    <city type="first">Rockport</city> 
    </Address>
    <email>love2fish@finmail.com</email> 
    </contactinfo>
    </Arrangement>
    <Arrangement>
    <FrequencyCd value="03">second first</FrequencyCd> 
    <FrequencyCd value="04">second second</FrequencyCd> 
    <contactinfo>
    <Address>
    <street>234 Straight Lane</street> 
    <city type="first">Crackport</city> 
    </Address>
    <email>hate2fish@finmail.com</email> 
    </contactinfo>
    </Arrangement>
    </Envelope>'
    )
)
SELECT filteredxml.FrequencyCd, filteredxml.City FROM origxml,
XMLTABLE ('$d/Envelope/Arrangement' PASSING origxml.xdoc AS "d"
                COLUMNS
                FrequencyCd     VARCHAR(20) PATH    'FrequencyCd[@value="01"]/text()',
                City            VARCHAR(30) PATH    'contactinfo/Address/city[@type="first"]/text()'
            ) as filteredxml
WHERE filteredxml.FrequencyCd IS NOT NULL
AND filteredxml.City IS NOT NULL
;