Wordpress oop wpdb in class

Question

I am new in OOP PHP and I am trying to use $wpdb (WORDPRESS) object in some of my custom classes but have no idea how to do it. Every time I try to implement basic operations with $wpdb results in fail. I need some basic stuff like get_results(),.... So how to do something like this:

global $wpdb;

$my_custom_table = $wpdb->prefix . "table_name";

$table_content = $wpdb->get_results("SELECT * FROM ".$my_custom_table);

and put it into my class like this:

Class MyClass{

     public function table_results(){
            //put in here
            return $this->table_content;
     }
}

I need that class in separate file so I could easily call to it.

Answer 1

Try this...

<?php
class MyClass {

private $wpdb;

public function __construct()
{
    global $wpdb;
    $this->wpdb = $wpdb;
}

public function table_results(){
    $my_custom_table = $this->wpdb->prefix . "table_name";

    $table_content = $this->wpdb->get_results("SELECT * FROM $my_custom_table");
    return $table_content;
}
}