问题描述：sql*plus中文乱码.
系统：oel 7.9
数据库：oracle 19.12
SQL> desc yb_ghij_mdhs;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ??                                                 DATE
 ??ID                                               VARCHAR2(36)
 ??                                                 VARCHAR2(36)
 ??CLOB                                             CLOB
 ??CLOB                                             CLOB
 ID                                        NOT NULL VARCHAR2(36)
 CZIP                                               VARCHAR2(36)
 CZY                                                VARCHAR2(36)
 CZDZ                                               VARCHAR2(36)
 ??                                                 VARCHAR2(4000)
 FHSJ                                               DATE
解决过程：
查数据库字符集.
SQL> select userenv('language') from dual;

USERENV('LANGUAGE')
----------------------------------------------------
AMERICAN_AMERICA.ZHS16GBK

SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0
[oracle@xd1dbadm01 ~]$ echo $NLS_LANG

[oracle@xd1dbadm01 ~]$ export NLS_LANG=AMERICAN_AMERICA.UTF8
[oracle@xd1dbadm01 ~]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Thu Nov 3 12:56:24 2022
Version 19.12.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0

SQL> desc yb_ghij_mdhs;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 日期                                               DATE
 号码ID                                             VARCHAR2(36)
 型号                                               VARCHAR2(36)
 传输CLOB                                           CLOB
 接收CLOB                                           CLOB
 ID                                        NOT NULL VARCHAR2(36)
 CZIP                                               VARCHAR2(36)
 CZY                                                VARCHAR2(36)
 CZDZ                                               VARCHAR2(36)
 结果                                               VARCHAR2(4000)
 FHZJ                                               DATE
说明：如上所示，sql*plus中文正常显示.