When using regular tables, its fine to use the following Oracle SQL query:
SELECT max(some_primary_key) FROM MyTable
ORA-00904: "SOME_PRIMARY_KEY": invalid identifier
SELECT max("some_primary_key") FROM MyTable
It doesn't have to do with objects or tables, it has to do with how these objects/tables have been created.
If you do
create table "blabla" then you always need to address this table with "blabla", if you do
create table blabla then you can address this table via BLABLA or blabla or bLabLa. Using
" " makes the name case sensitive and that is the reason why most developers don't use
" " because usually you don't want case sensitive names .