CAllCrmActivity::DeleteUnbound

static function DeleteUnbound($arBindings = null)
{
	$tableName = CCrmActivity::TABLE_NAME;
	$bindingTableName = CCrmActivity::BINDING_TABLE_NAME;
	global $DB;
	$dbRes = $DB->Query(
		"SELECT ID FROM {$tableName} WHERE ID NOT IN (SELECT ACTIVITY_ID FROM {$bindingTableName})",
		false,
		'File: '.__FILE__.'
Line: '.__LINE__
	);

	$delOptions = array(
		'SKIP_BINDINGS' => true,
		'SKIP_USER_ACTIVITY_SYNC' => true,
		'SKIP_STATISTICS' => true
	);

	if(ActivitySettings::getValue(ActivitySettings::KEEP_UNBOUND_TASKS))
	{
		$delOptions['SKIP_TASKS'] = true;
	}

	if(is_array($arBindings) && !empty($arBindings))
	{
		$delOptions['ACTUAL_BINDINGS'] = $arBindings;
	}

	$processedIDs = array();
	$responsibleIDs = array();
	while($arRes = $dbRes->Fetch())
	{
		$itemID = intval($arRes['ID']);

		$item = self::GetByID($itemID, false);
		if(!is_array($item))
		{
			continue;
		}

		$processedIDs[] = $itemID;
		$responsibleID = isset($item['RESPONSIBLE_ID']) ? intval($item['RESPONSIBLE_ID']) : 0;
		if($responsibleID > 0 && !in_array($responsibleID, $responsibleIDs, true))
		{
			$responsibleIDs[] = $responsibleID;
		}

		$delOptions['ACTUAL_ITEM'] = $item;
		self::Delete($itemID, false, false, $delOptions);
	}

	// Synchronize user activity -->
	if(is_array($arBindings) && !empty($arBindings))
	{
		foreach($arBindings as &$arBinding)
		{
			foreach($responsibleIDs as $responsibleID)
			{
				self::SynchronizeUserActivity($arBinding['OWNER_TYPE_ID'], $arBinding['OWNER_ID'], $responsibleID);
			}
			self::SynchronizeUserActivity($arBinding['OWNER_TYPE_ID'], $arBinding['OWNER_ID'], 0);
			\Bitrix\Crm\Activity\CommunicationStatistics::rebuild(
				$arBinding['OWNER_TYPE_ID'],
				array($arBinding['OWNER_ID'])
			);
		}
		unset($arBinding);
	}
	// <-- Synchronize user activity

	return $processedIDs;
}