oracle查询数据库参数sql语句

show parameters  service_names;

[root@dm02dbadm01 ~]# su - oracle
Last login: Wed Aug 31 14:50:27 CST 2022 on pts/3
 Please use the below environment file for Oracle 12c or 19c database 
     Oracle 12c Database env --------  source /home/oracle/12c.env 
     Oracle 19c Database env --------  source /home/oracle/19c.env 
[oracle@dm02dbadm01 ~]$ source /home/oracle/12c.env
[oracle@dm02dbadm01 ~]$ export ORACLE_SID=gooddb1
[oracle@dm02dbadm01 ~]$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Wed Aug 31 14:56:09 2022
Copyright (c) 1982, 2016, Oracle.  All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SYS@gooddb1> show parameters  service_names;
NAME             TYPE  VALUE
------------------------------------ ----------- ------------------------------
service_names          string  gooddb
SYS@gooddb1>