a drill question

[roller]

hello ,i have a drill `s question.when i excute this sql "select  ID  , Code , 
id as newId, case  when Code='auth' then '??' else 'ttt' end as newCode from ( 
select ID,Name,Code from mysql.auth_center.admin_menu where 1=1 ) as sqlInput
", it produce a exception,ths erro info is 
"org.apache.drill.common.exceptions.UserRemoteException: SYSTEM ERROR: 
CalciteException: Failed to encode '??' in character set 'ISO-8859-1' [Error 
Id: 8fdafdae-8368-45e3-a580-65a3b8213a98 on DESKTOP-P161MQ6:31010]";
   now,i how to solvet this.thake you for help;