[SOLVED] Kohana 3. Join with multiple condition using OR

I'm using Kohana Query Builder and trying do next:

$query
 ->join(«t1», «INNER»)
 ->on(«t1.id»,»=»,»t2.parent_id»)
 ->on(«t1.id»,»=»,»t3.x_id»)

This means:

INNER JOIN t1
ON(t1.id = t2.parent_id AND t1.id = t3.x_id)

But how force to use OR instead of AND of KO3 query builder join methods?

INNER JOIN t1
ON(t1.id = t2.parent_id OR t1.id = t3.x_id)

Due to Konaha source code all on() methods are concatinated with AND:

// Concat the conditions "... AND ..."
$sql .= ' ON ('.implode(' AND ', $conditions).')';

So you have at least 2 ways:

Redifine Database_Query_Builder_Join methods to support OR concatinator
(it's cheating) Use DB::expr() as 3rd parameter to on() method like:

->on('t1.id', '=', DB::expr('t2.parent_id OR t1.id = t3.x_id))