What is YQL ? Is it like jQuery ? How can i use it ?
Definition:
The Yahoo! Query Language is an expressive SQL-like language that lets you query, filter, and join data across Web services. With YQL, apps run faster with fewer lines of code and a smaller network footprint.
See more in yahoo reference.
No, it doesn't have anything with jQuery. It's like a SQL to webservices, etc.
jQuery is used to manipulate (x)HTML, handle events, handle animations, help in crossbrowsing, etc.
EDIT
YQL example:
select * from flickr.photos.search where text="Cat" limit 10
Access Flickr website and gets photo information.
jQuery example:
$(".search[text=Cat]").text();
Search current page, looking everthing with class search and have attribute text = Cat. Returns his text.
Here is a nice example using YQL and jQuery to build a FAQ list: http://tutorialzine.com/2010/08/dynamic-faq-jquery-yql-google-docs/
YQL(Yahoo query Language) helps you do select * from internet. Which means this is a SQL like query that helps you collect/join/filter/extract data from internet using simple SQL.
This is a very powerful tool atleast for me, you can easily do wonders using this.
Select * from html where url='example.com' is a small example of a major thing.
You can try this video which explains YQL to a new and basic user. http://blog.konarkmodi.com/tag/yql
YQL is a simple SQL like language but end up expanding into a REST URL, which will deliver you XML or JSON data so that you can quickly create a mashup.
When its comes to YQL always follow Christian Heilmann (http://www.twitter.com/codepo8). Here is His video http://developer.yahoo.com/yui/theater/video.php?v=heilmann-yql
Read this Wikipedia article that might give a little quick start http://en.wikipedia.org/wiki/YQL_Page_Scraping (this example uses HTML table of YQL)
Page Scraping can also be done using this chrome extension https://chrome.google.com/extensions/detail/bkmllkjbfbeephbldeflbnpclgfbjfmn
I am huge fan of YQL here is some more i created using YQL (pure javascript page , do a view source) http://www.purplegene.com/static/twenital.html
Google and you might find some more good examples.
here is another one from me! http://www.purplegene.com/static/androidversions.html