How do I know that Association is internally implemented by inner join or outer association

How do I know that Association is internally implemented by inner join or outer association

I have used the following syntax to directly return the corresponding description via path expression.

The data source comes from 1: N association.

The question is: how SAP internally implements this association? Via Inner join or outer join?

Two approaches to find answer by yourself:

Approach1:

Approach2:

ST05: Display execution plan