Yahoo Query Language: Difference between revisions

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'''Yahoo! query language''' ('''YQL''') is an [[SQL]]-like [[query language]] created by [[Yahoo!]] as part of their [[Yahoo! Developer Network|Developer Network]]. YQL is designed to retrieve and manipulate data from [[API]]s through a single Web interface, thus allowing [[mashup (digital)|mashups]] that enable developers to create their own applications.<ref>{{cite news |url=http://www.pcworld.com/businesscenter/article/164067/yahoo_extends_yql_web_data_query_platform.html |work=[[PC World (magazine)|PC World]] |title=Yahoo Extends YQL Web Data Query Platform |date=April 29, 2009 |last=Perez |first=Juan Carlos }}</ref>

{{short description|SQL-like query language}}

'''Yahoo! queryQuery languageLanguage''' ('''YQL''') is an [[SQL]]-like [[query language]] created by [[Yahoo!]] as part of their [[Yahoo! Developer Network|Developer Network]]. YQL is designed to retrieve and manipulate data from [[API]]s through a single Web interface, thus allowing [[mashup (digital)|mashups]] that enable developers to create their own applications.<ref>{{cite news |url=httphttps://www.pcworld.com/businesscenter/article/164067/yahoo_extends_yql_web_data_query_platform.html |work=[[PC World (magazine)|PC World]] |title=Yahoo Extends YQL Web Data Query Platform |date=April 29, 2009 |last=Perez |first=Juan Carlos }}{{Dead link|date=February 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> using [[Yahoo! Pipes]] online tool.

Initially launched in October 2008 with access to Yahoo APIs,<ref>{{cite news |url=http://www.eweek.com/c/a/Application-Development/Yahoo-Launches-YQL-Execute-Updates-YSlow-660481/ |archive-url=https://archive.today/20120731002123/http://www.eweek.com/c/a/Application-Development/Yahoo-Launches-YQL-Execute-Updates-YSlow-660481/ |url-status=dead |archive-date=July 31, 2012 |work=[[eWeek]] |title=Yahoo Launches YQL Execute, Updates YSlow |last=Kolakowski |first=Nicholas |date=April 29, 2009 }}</ref> February 2009 saw the addition of open [[data table]]s from third parties such as [[Google Reader]], the ''[[Guardian newspaper|Guardian]]'', and ''[[The New York Times]]''.<ref name="rww"/> Some of these APIs still require an [[API key]] to access them. On April 29th29 of 2009, Yahoo introduced the capability to execute the tables of data built through YQL using [[JavaScript]] run on the company's servers for free.<ref name="rww">{{cite news |url=http://www.readwriteweb.com/archives/theres_a_great_amount_of.php |work=[[ReadWriteWeb]] |last=O'Dell |first=Jolie |date=May 2, 2009 |title=Developers: Never Mind the APIs, Here's YQL Execute }}</ref> On January 3, 2019, Yahoo retired the YQL API service.

==YQL Page Scraping==

One of the most common use of YQL is getting data from any page on the internet(page scraping), thats why some of the people say yql can do

<pre>

"Select * from internet"

</pre>

==Examples==

For example to get data from this page you can do some thing like this

Filter RSS feeds

<pre>

<syntaxhighlight lang="sql">select title, link from rss where url = 'https://www.engadget.com/rss.xml'</syntaxhighlight>

Convert CSV to JSON or XML

select * from html where url="http://en.wikipedia.org/wiki/Yahoo!_query_language" and

<syntaxhighlight lang="sql">select * from csv where url='http://download.finance.yahoo.com/d/quotes.csv?s=YHOO,GOOG,AAPL&f=sl1d1t1c1ohgv&e=.csv' and columns='symbol,price,date,time,change,col1,high,low,col2'</syntaxhighlight>

xpath='//div[@id="bodyContent"]'

Extract HTML via CSS Selectors

</pre>

<syntaxhighlight lang="sql">SELECT * FROM data.html.cssselect WHERE url='http://www.w3.org/' AND css='ul.theme'</syntaxhighlight>

All data from YQL can be consumed in form of [[JSON]] or [[XML]]

One the example page where this data is scrapped is [http://www.purplegene.com/mashup?yql=select%2520*%2520from%2520html%2520where%2520url%253D%2522http%253A//en.wikipedia.org/wiki/Yahoo%2521_query_language%2522%2520and%250A%2520%2520%2520%2520%2520%2520xpath%253D'//div%255B@id%253D%2522bodyContent%2522%255D/p%255B1%255D'%26format%3Dxml%26diagnostics%3Dtrue%26callback%3Dren&t=Yahoo!%20query%20language%20-%20Wikipedia,%20the%20free%20encyclopedia here]

Get AppLinks meta data

==References==

<syntaxhighlight lang="sql">SELECT * from applinks WHERE url IN ('movietickets.com', 'pinterest.com')</syntaxhighlight>

<references/>

Parse any XML source

==External links==

<syntaxhighlight lang="sql">select Status.presence from xml where url = 'http://mystatus.skype.com/pjjdonnelly.xml' and Status.presence.lang = 'en'</syntaxhighlight>

* [http://developer.yahoo.com/yql/ Official site], including the YQL console

==Rate limits==

Use of the YQL should not exceed reasonable request volume.<ref>{{cite web|title=YQL|url=https://developer.yahoo.com/yql/|ref=yql}}</ref> Access is limited as below:

* 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.

==See also==

* [[SQL]]

*[[WSO2 Mashup Server]]

*[[Yahoo! Pipes]]

==References==

{{Reflist}}

==External links==

* [http://developer.yahoo.com/yql/ Official site], including the YQL console

{{Oath Inc.}}

{{Yahoo! Inc.}}

{{Query languages}}

[[Category:Yahoo!|query language]]

[[Category:Query languages]]

[[Category:Web scraping]]