YQL Tutorial

var map = new
YMap(document.getElementById('map'));
…
dev var currentGeoPoint = new
YGeoPoint( _c.Lat, _c.Lon );
map.addMarker(currentGeoPoint);
…

var map = new
…
…

…
if (flickcurl_prepare(fc,
"flickr.photos.geo.correctLocation",
parameters, count)) { … }
…

var map = new
…
…

…
…

http://search.yahooapis.com/
ImageSearchService/V1/imageSearch?
appid=YahooDemo&query=Corvette&results=2

var map = new
…
…

…
…

http://search.yahooapis.com/

http://weather.yahooapis.com/
forecastrss?p=FRXX0076&u=c

var map = new
…

?
…

…

?
…

? http://search.yahooapis.com/

?
http://weather.yahooapis.com/
forecastrss?p=FRXX0076&u=c

Demo time
http://developer.yahoo.com/yql/console/

Exercise 1

• write a query to search the web for “free
wifi” Washington DC
• find photos of kittens on flickr that were
tagged with “awesome”
• find the weather at SFO (san francisco
airport)

Solutions 1
• select * from search.web where query =
'"washington dc" free wiﬁ'
• select * from ﬂickr.photos.search where
text ="kittens" and tags="awesome"
• select * from weather.forecast where
location in (select postal from geo.places
where text="sfo")

Demo time part deux
http://developer.yahoo.com/yql/console/

Exercise 2

• Get my (“sh1mmer”) twitter stream
• Find articles about Obama in the New York
Times
• Google, Bing and Yahoo for dogs

Solutions 2
• select * from twitter.user.timeline where id =
"sh1mmer"
• select * from nyt.article.search where query =
"obama"
• select * from query.multi where queries =
'select * from microsoft.bing.web where
query="dogs";select * from google.search
where q = "dogs"; select * from search.web
where query="dogs"'

YQL in Practice
20 tiny steps to a working application

You’ll need:
Firefox
Firebug
Text editor

Step 1.
Login to the console with your Yahoo! login
http://developer.yahoo.com/yql/console

Step 2.
Find the statement box and
run the ﬁrst query with test.

Step 3.
Check out the formatted view.

Step 4.
Run the statement “desc html”

Step 5.
Find the keys,
note the required keys.

Step 6.
Get some HTML:
select * from html where url = "http://
hubblesite.org/gallery/album/the_universe"

Step 7.
Check out the result.
See the HTML in there?

Step 8.
Open http://hubblesite.org/gallery/album/the_universe
in Firefox.
Right click on a thumbnail and click “Inspect Element”

Step 9.
Find the element in Firebug.
Right click and select “Copy XPath”

Step 10.
Add and xpath = "" to your query.
Paste in the XPath from Firebug

Step 11.
Test your statement and
reﬁne your XPath.

Step 12.
Add limit 10 to your statement

Step 13.
Let’s get out of the console.
Copy the “Rest Query” url into a new tab

Step 14.
Let’s embed this in a web page.
Download the ﬁles from
http://github.com/sh1mmer/dotnet-yql-tutorial

Step 15.
Add
<script type="text/javascript"
src="yql_js_widget.js"></script>
to your HTML page.

Step 16.
Add some style:
<style type="text/css">
li.imgCnt{ list-style: none; background:#000000; margin: 3px; ﬂoat:
left; }
li.imgCnt img{ border:0; margin:5px; }
li.imgCnt div.imgTitle{ padding: 5px; font-size: 11px; text-
align:center; }
</style>

Step 17.
Add another script node.
Add conﬁg = {};

Step 18.
Format the output:
var format = '<li class="imgCnt">
<img src="{src}" alt="{alt}"></li>';

Step 19.
Add you query;
var yqlQuery = "" and add your query.

Step 20.
Add the render code:

yqlWidget.push(yqlQuery,conﬁg,format,'widge
tContainer');
yqlWidget.render();

Advanced
YQL
Advanced Queries, I/U/D, Open Tables and Using YQL
with JavaScript

Basics
select * from {table} where {key1} =
"{value1}" and {key2} = {value2}

select * from ﬂickr.photos.search where text
= "kittens" and tags = "domokun"

select
*
from
ﬂickr.photos.search
where
text = "kittens"
and
tags = "domokun"

Remote

select * from ﬂickr.photos.search where text =
"kittens" and tags = "domokun" and farm = 4

select * from ﬂickr.photos.search where text =
"kittens" and tags = "domokun" and farm = 4 limit 10

select * from ﬂickr.photos.search(10) where text =

"kittens" and tags = "domokun" and farm = 4 limit 10

Limit Summary

• limit 10 - give me max 10 results from the
data you have
• {table}(10) - get ten results from server
• {table}(0) - get enough results from the
server to ﬁll my local limit with the local
ﬁlters

select * from {table} (10) where foo = "bar" offset 10

vs.

select * from {table} (10,10) where foo = "bar"

select * from {table} (10) where foo = "bar" offset 10

<results>
<result foo=”bar”>1</result> <results>
<result foo=”qux”>2</result> <result foo=”bar”>1</result>

... ... <results>
</results>
<result foo=”qux”>8</result> <result foo=”bar”>9</result> </query>
<result foo=”bar”>9</result> <result foo=”bar”>10</result>
<result foo=”bar”>10</result> </results>
</results> </query>
</query>

select * from {table} (10,10) where foo = "bar"

<results>
<result foo=”bar”>11</result>
<results>
<result foo=”qux”>12</result>
...
...
</results>
</query>
</results>
</query>

select * from {table1}
where
{key1} in
(select id from {table2});

select * from ﬂickr.photos.info
where
photo_id in
(select id
from ﬂickr.photos.search
where text="kitten")

select * from {table1}
where
({key1}, {key2}) in
(select foo, bar from {table2});

select * from ﬂickr.places
where
(lat, lon) in
(select match1, match2 from regex
where
text in
(select entry.point from usgs.earthquakes limit 10)
and expression = "(-?d+.d+) (-?d+.d+)")
and total != 0 limit 10

select * from {table}(20) |
sort(ﬁeld=”foo”,
descending = “true”) |
truncate 10

Filters are always
applied last, in order

select * from {table}(20) | sort(ﬁeld=”foo”, descending = “true”) | truncate 10

<results> <results> <results>
<result foo=”bar”>1</result> <result foo=”bar”>20</result> <result foo=”bar”>20</result>
<result foo=”qux”>2</result> <result foo=”qux”>19</result> <result foo=”qux”>19</result>

... ... ...

<result foo=”qux”>18</result> <result foo=”qux”>3</result> <result foo=”qux”>13</result>
</results> </results> </results>
</query> </query> </query>

Super-secret Filters

• Xpath()
• Regex()
• ... there are more I can’t remember

I/U/D

• Personally, I like calling it DUI

I/U/D

• I’m always developing under the inﬂuence

I/U/D

• I’m always developing under the inﬂuence
• Insert / Update / Delete tables

Just like SQL except...

• INSERT - no where clause. period.
• UPDATE - only remote keys
• DELETE - only remote keys

INSERT INTO wordpress.post
(title, description, blogurl,
username, password) VALUES
("Test Title", "This is a test body",
"http://yqltest.wordpress.com",
"yqltestuser", "password");

Tom Hughes-Croucher
@sh1mmer
croucher@yahoo-inc.com

YQL Tutorial

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