Query the Web with YQL

Sriram Viswanathanhttp://slideshare.net/ramace

• Similar to SQL

• Can query, filter and join data across Web services

What is 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

Why YQL?

• http://developer.yahoo.com/yql/console/

• Enables you to run YQL statements interactively from your

browser

YQL Console

• 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

SELECT statement

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'

Filtering Query Results

Example

select * from social.profile where guid in (select guid from

social.connections where owner_guid=me)

Joining tables with sub-select

• 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

Paging and Limits

• YQL console includes a simple query builder tool. This tool

allows you to customize and explore YQL statements.

Using Query Builder

• 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>

Response Data

• 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

YQL using Javascript and PHP

• 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.

Usage Information and Limitations

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

References

Thank You!&

happy hacking