I want to create a database for myself. The data has complex grouping. I don't know which system to use to create my database. The data is in groups and sub-group forms, it almost has 5-6 layers of subgroups. I tried SQL but such complex sub-groups are not possible in it.
I really need to create the database. Hope for some good advice.

This is the type of grouping I want to do and I am searching for a kind of system that can save such data in a way that when I want to filter the data to find something I can get the results.
EG: if I search for high toughness properties of a material then MS and high carbon steel should appear.
Hope this helps.