View source for Yahoo Query Language

{{Redirect-distinguish|YQL|Lethbridge Airport}}
{{short description|SQL-like query language}}
'''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=https://www.pcworld.com/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 29 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.

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

Convert CSV to JSON or XML
<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>

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

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

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

==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]
{{Oath Inc.}}
{{Yahoo! Inc.}}
{{Query languages}}

[[Category:Yahoo!|query language]]
[[Category:Query languages]]
[[Category:Web scraping]]


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