SQL & PL/SQL

Hi,

I have done some research but just want to get some clarity

I have an index create index n1 on emp(comm);

now I want to add a sal column to this index n1, one option is droping and creating the index, can we just add one more column with out dropping, (as far as my konwledge and research done, we can't do it, but just confirming with you)

if we can't add it, I want to know the reason behind it, why we can't do it?


Thanks,
Sunil Noothi