Hi Debra
Basic questions are rejected when they fall under the categories of frequently ask question or basic training where there is a supply of material available. Also, the questions should be typically asked within the space for the topic (Training and Education Space is for SAP Education Products).
Where the item is frequently asked, you should be able to search for your answer or check out training.sap.com, help.sap.com, open.sap.com, experience.sap.com (lots of SAP sites depending on your topic).
There are times when basic questions have validity - such as new products and lack of material available. In these situations you need to demonstrate that you have search, explain the issue and what your understanding is and show that you have made attempts to resolve this.
When learning new items it might feel like participating in SCN is a challenge. However, posts are rejected to maintain the quality of SCN by remove noise of repeated questions.
In relation to your question, "subquery within a subquery" you asked "I would like to create a main report with a subquery and then within the subquery create another subquery. Is that possible?". This question is not very clear as you have not explained which part of SAP you are working on. Is it ABAP or another language. I rejected the post as the question appeared simplistic to me (although I am not a developer". Had it had more details I may have been able to point you in a better direction.
Good luck with your learning and hope you are able to find the information you are after. Some links to get you started with SCN:
Regards
Colleen
P.s. moving from Training & Education to SCN Support