FQL Overview of FQL Creating a simple query Using more advanced syntax Differences between SQL and FQL Q & A

Overview of FQL

Creating a simple query

Using more advanced syntax

Differences between SQL and FQL

Q & A

FQL: Overview Facebook Query Language introduced in the early spring of 2007 F8 appeared a little over two months ago Facebook API calls are just pre-packaged FQL queries

Facebook Query Language introduced in the early spring of 2007

F8 appeared a little over two months ago

Facebook API calls are just pre-packaged FQL queries

FQL: Overview Key advantages: Common syntax for all methods Condense Facebook queries Reduce response size

Key advantages:

Common syntax for all methods

Condense Facebook queries

Reduce response size

FQL: Overview FQL is an SQL-like syntax: SELECT name FROM user WHERE uid = 00000000

FQL is an SQL-like syntax:

SELECT name FROM user WHERE uid = 00000000

FQL: Simple Query Three parts to a query: SELECT a field FROM a table WHERE a condition is met

Three parts to a query:

SELECT a field

FROM a table

WHERE a condition is met

FQL: Simple Query Where do I live? SELECT current_location FROM user WHERE uid = 00000000

Where do I live?

SELECT current_location FROM user WHERE uid = 00000000

FQL: Simple Query <?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?> <users_getInfo_response xmlns=&quot;http://api.facebook.com/1.0/&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot; xsi:schemaLocation=&quot;http://api.facebook.com/1.0/ http://api.facebook.com/1.0/facebook.xsd&quot; list=&quot;true&quot;> <user> <uid>503802602</uid> <current_location> <city> Toronto </city> <state> Ontario </state> <country> Canada </country> <zip/> </current_location> </user> </users_getInfo_response>

FQL: Simple Query Has AND , OR , and NOT keywords Does simple math Uses basic boolean operators SELECT uid2 FROM friend WHERE uid1 = 00000000 AND uid2 > (00000000 + 700)

Has AND , OR , and NOT keywords

Does simple math

Uses basic boolean operators

SELECT uid2 FROM friend WHERE uid1 = 00000000 AND uid2 > (00000000 + 700)

FQL: Simple Query ... <friend_info> <uid2> 00000701 </uid2> </friend_info> <friend_info> <uid2> 00000702 </uid2> </friend_info> <friend_info> <uid2> 00000703 </uid2> </friend_info> ...

FQL: Simple Query Enhance queries with basic functions Examples include: now() strlen() substr() strpos()

Enhance queries with basic functions

Examples include:

now()

strlen()

substr()

strpos()

FQL: Advanced Query Use functions and math to construct more accurate responses: SELECT location FROM event WHERE eid = 2487044119 AND strpos(name,&quot;facebook&quot;) AND start_time >= 1186536600

Use functions and math to construct more accurate responses:

SELECT location FROM event WHERE eid = 2487044119 AND strpos(name,&quot;facebook&quot;) AND start_time >= 1186536600

FQL: Advanced Query <?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?> <fql_query_response xmlns=&quot;http://api.facebook.com/1.0/&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot; list=&quot;true&quot;> <event> <location> MaRS </location> </event> </fql_query_response>

FQL: Advanced Query Queries must be “indexable” Restricted by unique IDs, typically a table's primary ID (“uid”, “pid”, “eid”) Without an indexable WHERE condition, expect an error

Queries must be “indexable”

Restricted by unique IDs, typically a table's primary ID (“uid”, “pid”, “eid”)

Without an indexable WHERE condition, expect an error

FQL: Advanced Query ... <error_code> 604 </error_code> <error_msg> Your statement is not indexable - the WHERE clause must contain one of the columns marked with a star in http://developers.facebook.com/documentation.php?doc=fql</error_msg> <request_args list=&quot;true&quot;> <arg> <key>query</key> <value> SELECT name FROM event WHERE strpos(location,&quot;facebook&quot;) </value> </arg> ...

FQL: Advanced Query Subqueries allow very narrow results to be returned Chain queries together with IN clause Limited only by the data itself

Subqueries allow very narrow results to be returned

Chain queries together with IN clause

Limited only by the data itself

FQL: Advanced Query SELECT eid FROM event WHERE eid IN ( SELECT eid FROM event_member WHERE uid = 00000000 AND rsvp_status = &quot;attending&quot; ) AND location = &quot;mars&quot;

SELECT eid

FROM event

WHERE eid

IN (

SELECT eid

FROM event_member

WHERE uid = 00000000

AND rsvp_status = &quot;attending&quot;

)

AND location = &quot;mars&quot;

FQL: Advanced Query <?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?> <fql_query_response xmlns=&quot;http://api.facebook.com/1.0/&quot; xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot; list=&quot;true&quot;> <event> <eid> 2487044119 </eid> </event> </fql_query_response>

FQL: Advanced Query Some columns contain arrays Example: current_location also holds city , state , zip Usage: work_history.company_name

Some columns contain arrays

Example: current_location also holds city , state , zip

Usage: work_history.company_name

FQL: Versus SQL FQL != fecal

FQL: Versus SQL but... FQL != SQL

FQL: Versus SQL FQL is designed to be efficient Improving performance means restricting queries

FQL is designed to be efficient

Improving performance means restricting queries

FQL: Versus SQL No JOIN No ORDER BY No GROUP BY No LIMIT

No JOIN

No ORDER BY

No GROUP BY

No LIMIT

FQL: Versus SQL Limitations may mean too much data is returned Requires more complicated parsing

Limitations may mean too much data is returned

Requires more complicated parsing

FQL: Versus SQL Each FROM can only be against one table Not allowed: SELECT * FROM user, photo_tag WHERE uid = 00000000 AND subject = `flower`

Each FROM can only be against one table

Not allowed:

SELECT * FROM user, photo_tag WHERE uid = 00000000 AND subject = `flower`

FQL: Versus SQL Example: display the 5 most recently updated events in Toronto

Example: display the 5 most recently updated events in Toronto

FQL: Versus SQL In SQL: SELECT * FROM event WHERE location = &quot;mars&quot; AND user = 00000000 ORDER BY update_time ASC LIMIT 5

In SQL:

SELECT * FROM event WHERE location = &quot;mars&quot; AND user = 00000000 ORDER BY update_time ASC LIMIT 5

FQL: Versus SQL In FQL: SELECT update_time, eid, name, location, venue FROM event WHERE eid IN ( SELECT eid FROM event_member WHERE uid = 00000000 ) AND location = &quot;mars&quot; Then sort the array, and slice it: arsort($result); array_slice($result,0,5);

In FQL:

SELECT update_time, eid, name, location, venue

FROM event WHERE eid

IN (

SELECT eid FROM event_member WHERE uid = 00000000

)

AND location = &quot;mars&quot;

Then sort the array, and slice it: arsort($result); array_slice($result,0,5);

FQL: Tips Use the developer tools ( fql.query ) See what is available by investigating the API documentation Share what you learn on your blog and the developer Wiki

Use the developer tools ( fql.query )

See what is available by investigating the API documentation

Share what you learn on your blog and the developer Wiki

FQL Questions? Craig Saila saila.com [email_address]