/**
* Include depth level into the result.
*
* @param string $as
*
* @return $this
*/
public function withDepth($as = 'depth')
{
if ($this->query->columns === null) {
$this->query->columns = ['*'];
}
$table = $this->wrappedTable();
list($lft, $rgt) = $this->wrappedColumns();
$alias = '_d';
$wrappedAlias = $this->query->getGrammar()->wrapTable($alias);
$query = $this->model->newScopedQuery('_d')->toBase()->selectRaw('count(1) - 1')->from($this->model->getTable() . ' as ' . $alias)->whereRaw("{$table}.{$lft} between {$wrappedAlias}.{$lft} and {$wrappedAlias}.{$rgt}");
$this->query->selectSub($query, $as);
return $this;
}
