Request for all elements of a section in Bitrix?

Question

PHP

It is necessary to pull out elements from the section and all its subsections by request and perform actions with them.

Answer 1

You can get a list of mixed list of all sections and elements:

//CIBlockResult
CIBlockSection::GetMixedList(
 array arOrder = Array("SORT"=>"ASC"),
 array arFilter = Array(), // тут надо указать родителя 
 bool bIncCnt = false,
 array arSelectedFields = false
);

read here

Answer 2

If the elements are needed directly, why is the usual GetList with SECTION_ID and INCLUDE_SUBSECTIONS in arFilter not suitable?
https://dev.1c-bitrix.ru/api_help/iblock/classes/c...
Shl. Sorry, didn't see the discussion in the comments to the answer above, where the same solution is suggested.