MySQL: Find records in one table that are not in another

Using NOT EXISTS is much faster than using LEFT JOIN to find records in one table that are not in another. Head over at for more details on the same

PHP micro-optimization tips

• calling an object method is faster then traping it with with "__call"
• calling a "static" method is faster then an object method
• calling a function is faster then calling a static method
• accessing a local variable is faster then then a global variable
• accessing a global variable is faster then an object property
• accessing an object property is faster then trapping it with "__get" and "__set"
• accessing an initialized variable is faster then accessing an uninitialized variable
• absolute paths in "include" and "require" are faster then relative
• merging several scripts in one file and then including it is faster then several includes
• "switch" is faster then "if ... else if ..." in some cases
• do not use regexs for simple string processing tasks
• avoid @ (error control operator)
• avoid notices and warnings in your scripts
• avoid unused variables and unused method parameters
• adding method parameter increases calling time
• adding method parameter type hint increases calling time
• unset variables that contain large amount of data or circular references
• $_SERVER['REQUEST_TIME'] contains script startup time
• cache page output or result of resource-consuming functions
• "echo" is faster than "print"
• "echo" accepts several arguments, you can use it instead of string concatenation
• "ob_start()" and "ob_end_clean()" is may be better then several string concatenations
• strings in single quotes ('...') are processed faster then strings in double quotes ("...")
• pre-increment (++$i) is faster then post-increment ($i++)
• "isset" is a faster alternative to "array_key_exists"
• an array is a faster alternative to a class with several fields
• "foreach" is better then "for" in many cases
• open resources (files, database connections, sockets) right before using them, free resources as soon as you do not need them
• do not fetch database fields which you do not use in your script
• use prepared database statements
• combine several queries in one when database supports it

Data structures in PHP 5.3

In the programming world there are quite a few well understood and explored data structures. Which are commonly used in tons of applications, still the only things PHP offered till 5.3 in regards to structuring data were arrays (more precise: hash tables) and objects. So people had to either abuse them for other structures or implement the structures themselves on top of these. Thanks to Etienne things now are changing and PHP's Standard PHP Library (SPL) extension will offer quite a few standard implementations of data structures. The implemented data structures are implemented using these classes:

* SplDoublyLinkedList
* SplStack
* SplQueue (SplPriorityQueue)
* SplHeap (SplMinHeap, SplMaxHeap)
* SplFixedArray

For more details head over at http://schlueters.de/blog/archives/90-Data-structures-in-PHP-5.3.html

Usage of IF condition in mysql

Scenario:

Suppose we have the field in the table lets say status which has the ENUM value ACTIVE,INACTIVE.Usually after getting the value of this field(through the query)

we used to write return ($result['status']=='ACTIVE')?1:0 in class methods.

Here we are getting the db result array and based on the check(ACTIVE/INACTIVE) we are returning the boolean value.Instead of that we can have that check in the query itself like below

SELECT IF(status='ACTIVE',1,0) AS statuscheck from table1

Note that in the condition we need to give single equal symbol

so the code return ($result['status']=='ACTIVE')?1:0 will be replaced by return $result['statuscheck'].

Google Turns its Back on Firefox

About a month ago, Google dropped StarOffice from the Google Pack, a downloadable package of free Internet and productivity software for Windows users. StarOffice is a desktop office suite based on the open source OpenOffice.org program and distribute by Sun, and we theorized that Google was laying the ground work for a future push to get users to dump their desktop software in favor of Google’s own web-based application offerings.

For more details head over at http://www.sitepoint.com/blogs/2008/12/15/google-turns-its-back-on-firefox/

CodeIgniter - Open source PHP web application framework

For more details check it in http://roshanbh.com.np/2008/12/codeigniter-programmer-php.html

Introduction To Xajax

The Xajax library provides a useful and simple method of generating asynchronous requests with next to not knowledge of javascript. All the javascript code is generated internally and leaves the developer to simply implement PHP functions. This tutorials is an absolute basic beginners guide to getting started with xajax. Full source code is provided with an explaination of how the process works.

More details on this, check it on http://www.phpro.org/tutorials/Introduction-To-Xajax.html

Quick and Easy Graphing with the Google Chart API

Google has created an API for displaying the data in terms of chart which will be helpful in visualizing the data for reporting.For more details head over at http://www.sitepoint.com/blogs/2008/11/28/quick-and-easy-graphing-with-the-google-chart-api/

Application Configuration

PHP applications come in many shapes and sizes. Some used locally from command line, and more commonly, for web based applications. More often than not, regardless of size or type, some form of configuration variables will be stored for global access. Usually these configuration options are held in one of these four types of containers.

* ini file
* XML file
* PHP file
* Database

Each options has its pros and cons. Here each of these options is explored to see which method is right for your application.

For more details head over at http://www.phpro.org/articles/Application-Configuration.html

GROUP_CONCAT in MySQL

I had the scenario for the table like below.

Table: test

id title
_________________

1 T2
1 T3
1 T1
2 L2
2 L1

I want the results like

id title
_________________

1 T2,T3,T1
2 L2,L1


For this, SQL would be

select id,GROUP_CONCAT('title') from test GROUP BY id ORDER by id


Now i want the values of title to be sorted.

This can be done using the below query

select id,GROUP_CONCAT('title' ORDER BY title) from test GROUP BY id ORDER by id

The results would be

id title
_________________

1 T1,T2,T3
2 L1,L2