Find Oracle database version

How to find which version of Oracle version is installed?


SQL> col product for a40
SQL> col version for a10
SQL> col status for a15

SQL> select * from product_component_version;

PRODUCT                  VERSION                                              STATUS
----------------------------------------                                   ---------- ---------------
NLSRTL                     11.2.0.1.0                                                        Production
Oracle Database 11g Enterprise Edition     11.2.0.1.0 64bit               Production
PL/SQL                     11.2.0.1.0                                                          Production
TNS for Linux:                 11.2.0.1.0                                                   Production


or


SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0    Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production


or

SQL> select comp_id,version,comp_name,status from dba_registry;

COMP_ID                VERSION      COMP_NAME                   STATUS
------------------------------ ---------- ---------------------------------------- ---------------
OWB                   11.2.0.1.0 OWB                                               VALID
APEX                   3.2.1.00.1 Oracle Application Express           VALID
EM                   11.2.0.1.0 Oracle Enterprise Manager                        VALID
AMD                   11.2.0.1.0 OLAP Catalog                                   VALID
SDO                   11.2.0.1.0 Spatial                                                 VALID
ORDIM                   11.2.0.1.0 Oracle Multimedia                          VALID
XDB                   11.2.0.1.0 Oracle XML Database                           VALID
CONTEXT                11.2.0.1.0 Oracle Text                                     VALID
EXF                   11.2.0.1.0 Oracle Expression Filter                          VALID
RUL                   11.2.0.1.0 Oracle Rules Manager                              VALID
OWM                   11.2.0.1.0 Oracle Workspace Manager                     VALID
CATALOG                11.2.0.1.0 Oracle Database Catalog Views        VALID
CATPROC                11.2.0.1.0 Oracle Database Packages and Types       VALID
JAVAVM                   11.2.0.1.0 JServer JAVA Virtual Machine           VALID
XML                   11.2.0.1.0 Oracle XDK                                            VALID
CATJAVA                11.2.0.1.0 Oracle Database Java Packages        VALID
APS                   11.2.0.1.0 OLAP Analytic Workspace                       VALID
XOQ                   11.2.0.1.0 Oracle OLAP API                                    VALID

18 rows selected.

or

SQL> SELECT VERSION FROM V$INSTANCE;

VERSION
----------
11.2.0.1.0


There could be many more ways you could find this info...