Getting started with YQL

1. Query the Web with YQL
Sriram Viswanathan
http://slideshare.net/ramace

2. What is YQL?
•Similar to SQL
•Can query, filter and join data across Web services

3. Why YQL?
• Simple, SQL-like
• Hides complexity of Web service API
• Pre-defined tables for popular Yahoo! Web services such as
Flickr, Social and others.
• Supports output format XML, JSON

4. YQL Console
• http://developer.yahoo.com/yql/console/
• Enables you to run YQL statements interactively from your
browser

5. SELECT statement
• SELECT what FROM table WHERE filter
Examples
• select * from social.connections where owner_guid=me
• select contactId from social.connections where owner_guid=me
• select image.imageUrl from social.profile where guid=me

6. Filtering Query Results
Examples
•select * from flickr.photos.search where text='Barcelona’ and
api_key=‘your api key’
•select * from upcoming.events where location in ("San Francisco",
"San Jose”)
•select * from flickr.photos.info where photo_id='7640771676' and
api_key=’your api key'

7. Joining tables with sub-select
Example
select * from social.profile where guid in (select guid from
social.connections where owner_guid=me)

8. Paging and Limits
• select * from flickr.photos.search where text="Cat" and
api_key=”your api key" limit 10
• select * from flickr.photos.search(0,10) where text="Cat" and
api_key=”you api key”
• select * from flickr.photos.search(0,10) where text="Cat" and
api_key=“you api key” limit 5
• select * from flickr.photos.search where text="Cat" and
api_key=“you api key” limit 5 offset 3

9. Using Query Builder
• YQL console includes a simple query builder tool. This tool
allows you to customize and explore YQL statements.

10. Response Data
• Supported response XML, JSON
• Contains diagnostic and results elements
<query ... (attributes such as count)>
<diagnostics>
... (sub-elements such as publiclyCallable)
<results>
... (data returned by the call to YQL)
</results>
</query>

11. YQL using Javascript and PHP
• YUI YQL Utility for Javascript
http://yuilibrary.com/yui/docs/yql/
• YQL call from PHP
http://developer.yahoo.com/yql/guide/yql-code-
examples.html#yql_php

12. Usage Information and
Limitations
• YQL has a performance uptime target of over 99.5%.
• YQL relies on the correct operation of the Web services and
content providers it accesses.
• Per application limit (identified by your Access Key): 100,000
calls per day.
• Per IP limits: /v1/public/*: 2,000 calls per hour; /v1/yql/*: 20,000
calls per hour.
• YQL rate limits are subject to the rate limits of other Yahoo! and
3rd-party Web services.

13. References
http://developer.yahoo.com/yql/
http://developer.yahoo.com/yql/guide/
http://yuilibrary.com/yui/docs/yql/
http://developer.yahoo.com/yql/guide/yql-code-
examples.html#yql_php

14. Thank You!
&
happy hacking