SqlHelper::convertToDbDate

public function convertToDbDate($value)
{
	if (empty($value))
	{
		return "NULL";
	}
	elseif($value instanceof TypeDate)
	{
		return $this->getCharToDateFunction($value->format("Y-m-d"));
	}
	else
	{
		throw new MainArgumentTypeException('value', 'BitrixMainTypeDate');
	}
}