Group::getGroupLastActivityDate

static function getGroupLastActivityDate(int $groupId): ?MainTypeDateTime
{
	if (!static::includeModule())
	{
		return null;
	}

	$query = WorkgroupTable::query()
		->setSelect([
			'DATE_CREATE',
			new ExpressionField('ACTIVITY_DATE', 'MAX(%1$s)', ['T.ACTIVITY_DATE']),
		])
		->registerRuntimeField(
			'T',
			new ReferenceField(
				'T',
				TaskTable::getEntity(),
				Join::on('this.ID', 'ref.GROUP_ID'),
				['join_type' => 'left']
			)
		)
		->where('ID', $groupId)
	;

	$lastActivityDate = null;

	$res = $query->exec();
	if ($row = $res->fetch())
	{
		$lastActivityDate = ($row['ACTIVITY_DATE'] ?? $row['DATE_CREATE']);
	}

	return $lastActivityDate;
}