I have a question and maybe somebody can help me figure out what the best way would be to achieve the solution. What i wanted to do is the reverse of:

http://doc.silverstripe.com/framework/en/topics/datamodel#highlighter_745635

WHERE ("LastName" = 'Minnée' AND ("FirstName" = 'Sam' OR "Age" = '17'))

I want to get something along the lines of:

WHERE( ("LastName" = 'Minnée') OR ("FirstName" = 'Sam' AND "Age" = '17'))

Now i cannot find any way to achieve this effect seeing as i cannot add a filter within the filterAny

Well you can always use a direct ->where() clause for this - you'll need to prevent against SQL injection manually but that isn't the end of the world.

I am indeed already using the where method and all was just wondering if their was a build in way to achieve the same result.

You may be able to use the subtract method on a data list more info is here under Subtract
http://doc.silverstripe.com/framework/en/topics/datamodel

Also a example to give you an idea

$allSams = Member::get()->filter(array('FirstName' => 'Sam', 'Age' => 17));
$allMinnee = Member::get()->filter('SurName', 'Minnée');
$noSams = $allMembers->subtract($allSams);

Member::get()->alterDataQuery(function($query) {
  $disjunct = $query->disjunctiveGroup();
  
  $t = new ExactMatchFilter('LastName', 'Minnée', array());
  $t->apply($disjunct);  

  $conjunct = $disjunct->conjunctiveGroup();
  $t = new ExactMatchFilter('FirstName', 'Sam', array());
  $t->apply($conjunct); 
  $t = new ExactMatchFilter('Age', '17', array());
  $t->apply($conjunct); 
});

That is what it would expand to if something nicer existed. However, this is closer you'll get to something inbuilt.

Two great suggestions even if they are a tad cumbersome to the problem at hand. Guess those are the only ways to do it with build in functionality. Guess we can only hope to see different solutions to allow nested structures something like:

array(
   "OR" => array(
           'LastName' => 'Minée',
           'AND' => array(
                  'FirstName' => 'Sam',
                  'Age'  =>  17
            )
     )
)

+1 for your suggestion Schippie
I'm neither of the correct methods are readable/logical looking to me

On the same note - if I might make a tiny hijacking - I still use explicit SQL for EXISTS statements is there a suggestion on how to handle these in the ORM? Or can I add this to the above suggestion?
(this might be worth moving to the dev list...)

Oh sure Swaiba, would be nice to see both changed. And i am not sure EXISTS has a build in functionality for it.
So would be nice to see both functionality's added.