Category::with('params.values')->get();
$users = User::with(['posts' => function($query)
{
$query->where('title', 'like', '%первое%');
}])->get();
$users = User::with(['posts' => function($query)
{
$query->where('title', 'like', '%первое%');
},
'foo',
'bar' => function($query){
// bar query
}])->get();
Category::with('params.values')->whereHas('params', function($query){
$query->where('something', 'foobar');
})->get();