/**
* Compare in the following style in the where condition:
* $column IS NULL.
*
* @param string $column Column name for the comparison.
*
* @return $this The same instance to concatenate methods.
*/
public function isNull($column)
{
/** @var ColumnInterface $columnObj */
$columnObj = $this->factory->references('Column', $column);
$this->condition->isNull($columnObj);
return $this;
}
