Oracle从xml中提取截断值

我们有一个 CLOB 列，在其中存储相当简单的 XML，我需要从中提取其中一个标签的属性。我相信 select 语句是正确的，因为我得到了该值的一部分，但它会将其截断为 80 个字符。

这是 XML 的片段...

<?xml version="1.0" encoding="UTF-8"?>
<service_orders count="1">
   <service_order order_number="fakefakefake" id="fakefakefake">
      <customer>
         <customer_id>ABCDE12346</customer_id>
         <first_name>FAKE</first_name>
         <last_name>CUSTOMER</last_name>
      </customer>
...
    <images count="2">
       <image src="https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here" thumbnail="https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here_thumb"/>
</images>
...

...这是 SQL 的片段...

select
    xmltype(contact_data).extract('/service_order/@order_number').getStringVal ordnum
   ,extract(xmltype(contact_data) ,'//images/image/@src') imgsrc
from
    my_table
where
    trunc(contact_date) = trunc(sysdate)
and extractvalue(xmltype(contact_data) ,'/service_order/@order_number') = '&ordnum'

返回 URL 的开头，但如前所述，URL 被截断为 80 个字符。

我究竟做错了什么？

你在sqlplus中执行这个吗？ Extract返回一个XMLType实例，并根据long http://docs.oracle.com/cd/B19306_01/server.102/b14357/ch12040.htm#i2699121变量，默认为 80。如果增加该值，您可以看到完整的 URL。

SQL> with x(contact_data) as (
select '<?xml version="1.0" encoding="UTF-8"?>
<service_orders count="1">
   <service_order order_number="fakefakefake" id="fakefakefake">
      <images count="2">
       <image src="https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here"/>
        </images>
</service_order>
</service_orders>' from dual
)
select
    length(extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src')) as url_length,
    extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src') as url
from
    x;  

URL_LENGTH
----------
URL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
       101
https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_b

增加 long 变量的值后，

SQL> set long 120

SQL> with x(contact_data) as (
select '<?xml version="1.0" encoding="UTF-8"?>
<service_orders count="1">
   <service_order order_number="fakefakefake" id="fakefakefake">
      <images count="2">
       <image src="https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here"/>
        </images>
</service_order>
</service_orders>' from dual
)
select
    length(extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src')) as url_length,
    extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src') as url
from
    x;  

URL_LENGTH
----------
URL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
       101
https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here

您可以使用 getStringVal 函数将 XMLType 转换为 varchar2，它不依赖于 long 变量。

SQL> set long 80

SQL> with x(contact_data) as (
select '<?xml version="1.0" encoding="UTF-8"?>
<service_orders count="1">
   <service_order order_number="fakefakefake" id="fakefakefake">
      <images count="2">
       <image src="https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here"/>
        </images>
</service_order>
</service_orders>' from dual
)
select
    length(extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src')) as url_length,
    extract(xmltype(contact_data),'/service_orders/service_order/images/image/@src').getStringval() as url
from
    x; 

URL_LENGTH
----------
URL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
       101
https://s3.amazonaws.com/some_subfolder/deeper/deeper_still/ever_deeper/really_big_long_url_goes_here