How to check the oracle db version?

The oracle db version that you are using can be know by using the below simple SQL query:

                                                         select * from v$version;

Sample output is as below:

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
.
.
.
.
.