Tax Code - BSEG BSET link

Hi Guys,

I'm trying to find out if a Tax Code was ever used for a posting.

For these we are looking if there are any records for that specific Tax Code at BSEG (using BSAD, BSAK, BSAS, BSID, BSIK and BSIS tables) and BSET table.

My question is: It is necessary to look over BSET table if we already check BSEG? Is it possible to have a record in BSET that is not present in BSEG?

I don't have very clear the link between these 2 tables.

Thanks!

Gabriela