plsql 登录后，提示数据库字符集（AL32UTF8）和客户端字符集（ZHS16GBK）不一致

Database character set (AL32UTF8) and Client character set (ZHS16GBK) are different.
Character set conversion may cause unexpected results.

Note: you can set the client character set through the NLS_LANG environment variable or the NLS_LANG registry key in
HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_OraClient11g_home2.

解决办法：修改环境变量

找到 NLS_LANG 键，他的值原来是：SIMPLIFIED CHINESE_CHINA.ZHS16GBK

修改为：SIMPLIFIED CHINESE_CHINA.AL32UTF8

重新打开plsql ，登录，好了。