Innerjoin a custom table the normal WP-Query

This is my table:

Name: customTable
Fields: ID | title | date | content | url

and now I want to “inner join” this table into the the normal WP-Query, but only when I am in the category “news”.

This is what I have

function meta_filter_posts( $query )
{

   if(is_category('news'))
   {
       // and here I want to add my custom table (like inner join)
       // sorted by date

        $query->set('orderby','date');
        $query->set('order', 'DESC');   

       /*  innerJoin the table customTable */


   }

}
add_filter( 'pre_get_posts', 'meta_filter_posts' );

Any ideas how to include this table? Thanks in advance!