Add condition group in Views filter handler

Question

I have a Views filter handler, which does

$this->query->add_where(
  $this->options['group'],
  $this->real_field,
  vms_get_current_mlid(),
  $this->operator = ($this->operator == '=') ? 'IN' : 'NOT IN'
);

Which initially looks fine, but fails with "NOT IN", when the field value is NULL, as NOT IN (100) does not return TRUE for a NULL value, which is what I would like.

When the operator is 'NOT IN', I need to add a "OR IS NULL" operator as well, but still keep it within the same group.

If the filters are

Node is "page" AND NID_REFERENCE NOT IN (100, 101, 102)

I would like that to become

Node is "page" AND (NID_REFERENCE NOT IN (100, 101, 102) OR NID_REFERENCE IS NOT NULL)

How do I do that?

Answer 1

The answer turns out to be that add_where() also accepts a DatabaseCondition argument, meaning I could do

$this->query->add_where(
  $group,
  db_or()
    ->condition($table, $vms_target, 'NOT IN')
    ->condition($table, $vms_target, 'IS NULL')
)

Answer 2

I couldn't quite wrap my head around those queries in your last comment, but instead I tried exploring how Views does between operations. Check out db_or() which is used by views_handler_filter_numeric::op_between() - I think that will do it.