class to class function call

Okay, I have two classes set up. Both classes have functions. For example, we will call them class1 and class2.

so i have class1 and class2 called like so:

$class1 = new class1;

$class2 = new class2;

now then, can class2 reach into class one and grab a function? and if so, how do I accomplish that?  do i have to do:

class class2

{

function tester() {

class1func();

}

or do i have to do:

class class2

{

function tester() {

global $class1

$class1->class1func();

}

???

the reason i ask is i created a mysql class that has my most used mysql functions simplified for me, and I want to use my mysql query function from the mysql class in my news class to draw the news from the database.

2 ways.

1. Object A uses instance of Object B

<?php
class a {
  function a () {
    $this->b = new b;
  }

  function get() {
    return $this->b->val;
  }
}
?>

2. Object B extends Object A

<?php

class a {
   public $val = "hio";
   function a() {
     $this->val = "hello";
   }
}

class b extends a {
  function b() {
    a::a();
    print $this->val;
  }
}

That second example should be...

<?php

class a {
   public $val = "hio";
   function a() {
     $this->val = "hello";
   }
}

class b extends a {
  function b() {
    $this->a();
    print $this->val;
  }
}

?>

Thanks for that.. my bad for typing the example in the box