Question

I’m using the YQL Console to experiment with querying a REST XML web-service.

I found a simple public service to play with.

http://www.thomas-bayer.com/sqlrest/CUSTOMER/-151612345/

returns

<CUSTOMER xmlns:xlink="http://www.w3.org/1999/xlink">
  <ID>-151612345</ID>
  <FIRSTNAME>Deepthi</FIRSTNAME>
  <LASTNAME>Deep</LASTNAME>
  <STREET>440 - 20th Ave.</STREET>
  <CITY>Los Angeles</CITY>
</CUSTOMER>

If I use the query:

select * 
from xml 
where url='http://www.thomas-bayer.com/sqlrest/CUSTOMER/-151612345/'

I get this XML returned. However, if I try to restrict to data to a single element, e.g.:

select * 
from xml 
where url='http://www.thomas-bayer.com/sqlrest/CUSTOMER/-151612345/' 
  and xpath='//LASTNAME'

no results are returned.

What am I doing wrong?

Click here to display the YQL console with the query loaded.

Answer 1

The correct key for filtering the results as you want is not xpath, instead it is itemPath.

SELECT *
FROM xml
WHERE url='http://www.thomas-bayer.com/sqlrest/CUSTOMER/-151612345/'
  AND itemPath='//LASTNAME'

^{(Try this query in the YQL console)}

You can see the keys for a given table by issuing the query desc <tablename>.

desc xml

^{(Try this query in the YQL console)}

In the case of the xml table, the itemPath can either be an XPath expression or an E4X dotted path.