Web APIs: Yahoo! Query Language

18.Jan.2009

Again on web APIs, Yahoo launched in late 2008 its own data query language, YQL. It is similar to SQL, where the tables are Yahoo’s APIs: flickr, mybloglog, upcoming and many other services. As a quick example, this is how you query for 10 flickr photos with cats:

SELECT * FROM flickr.photos.search WHERE text="Cat" LIMIT 10

The queries still have to go through a REST API, so in the end you’ll be doing this request:

http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20
flickr.photos.search%20where%20text%3D%22Cat%22%20limit%2010&format=xml

This query language is however very limited when comparing to SQL. It only supports WHERE, OFFSET, LIMIT and IN statements with sub-selects inside, and no modifying queries like INSERT, UPDATE or DELETE. More recently, support for microformats was added.

Seriously, I don’t believe this kind of API will get widely used. It increases the barrier for non-programmer folks and the final query result is everything but a pretty url. However, I find the idea of adopting an existing standard important and SQL has it’s advantages. You don’t have to find out how to iterate through all those different APIs, you just have to use LIMIT and OFFSET. And the sub-selects seem to be an interesting concept for a role usually played by a tool like Yahoo Pipes:

SELECT * FROM social.profile WHERE guid   
IN (SELECT guid FROM social.connections WHERE owner_guid=me)

For more information, check out the YQL documentation.

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1 Comment

Wow this is very good! Unfortunately, I see that Delicious bookmarks are not included in the data sets available yet.... :(
Joaquim Rendeiro joaquim rendeiro / 25.Jan.2009 at 02:01pm

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