protected function applyFilterColumn($query, $columnName, $keyword, $boolean = 'and')
    {
        $query    = $this->getBaseQueryBuilder($query);
        $callback = $this->columnDef['filter'][$columnName]['method'];

        if ($this->query instanceof EloquentBuilder) {
            $builder = $this->query->newModelInstance()->newQuery();
        } else {
            $builder = $this->query->newQuery();
        }

        $callback($builder, $keyword);

        $query->addNestedWhereQuery($this->getBaseQueryBuilder($builder), $boolean);
    }