(Almost) Everthing an experienced programmer needs to know to get started with PHP

I consider myself to be an experienced programmer. Having spent the last 10 years working on a variety of platforms like Windows and Linux, using different programming languages like Java, C#, VB, Ruby, JavaScript etc, I feel that I have a broad experience and understanding of programming. However, there is always that moment when one must use a different language, for whatever reason. In my case I had to start tinkering with a site developed by someone else in PHP. Now I have always tried to avoid PHP since I was very much into compiled languages like Java and C#. Since breaking away from the corporate world, I have been able to move to scripting languages like Ruby, JavaScript and now PHP.

What I want to do is briefly summarize what an experienced programmer needs to know to get started with PHP. I managed to build a simple site in PHP in less than one week using PHP / MySQL / Apache on Linux (commonly known as LAMP stack). I will just list some of the things that I found useful during the journey. The site I built by the way is for my very own Computer School in Cambodia (shameless personal project plug, I suppose, but only if your in Cambodia .

Note: To place PHP script inside a page you need to open with

Setting variables:

$somevar = "hello world";

String concatenation is done with dots!

$url="/somthing/".$id."/".$name.".html";

Connecting to a database

mysql_connect(localhost,$username,$password);
mysql_select_db($database) or die( "Unable to select database");

Execute a query and count results

$results=mysql_query($query_sql_string);
$num_results=mysql_numrows($results);

Get a value from the resultset

//Note this can be in a while loop.
//$i is a counter.
$id=mysql_result($results,$i,"id");

IF statements

if (!is_null($id)) { // do something }

Output values in HTML rendering

<h1 align="center"><?=$some_value?></h1>

Date formatting

More details of date formatting in PHP

$date_obj->format("D j M Y")

Server Side Includes

include('db.php');