Question

First time I searched for how to connect to databases with PHP I’ve stumbled upon this example:

mysql_connect("$host", "$username", "$password");

But what’s the difference between that and this?

mysql_connect($host, $username, $password);

Answer 1

No difference form user perspective actually. The variable-in-double-quote will be evaluated, so;

$hello="world";
$world="hello"; 
echo "$hello $world"

will print “world hello”.

This feature allows you to do

"$very $annoying $string"
instead of
$very." ".$annoying." ".$string

This is like shell script (if you’re familiar with shell script).