setting sid on sqlplus

[bonny]

I have to set SID for creating new database on sqlplus.how to do that.I already have oracle database on the same computer.This is possible on command line but not on sqlplus.please suggest.
tahnks

[stecal]

Can't. You can connect to a different database/SID via SQL*Plus, but you cannot set the ORACLE_SID in a SQL*Plus session. So what may not be obvious to you is this: set ORACLE_SID in the shell window (assuming UNIX), then do sqlplus /nolog, conn / as sysdba, create database, etc.