How to Find SYS Privilege Users
To your question:

I want to know which users have SYS and SYSDBA privilege before export/import operation.

SYSDBA is a role, not a user or schema. The SYSDBA role is like &quot;root&quot; on unix or &quot;Administrator&quot; on Windows. It sees all, can do all. Internally, if you connect as sysdba, your schema name will appear to be SYS.
As per the Burleson consulting blog, the v$pwfile_users view contains a list of all users who have been granted the SYSDBA or SYSOPER roles.
SQL&gt; desc v$pwfile_users;

Name Null?  Type
----------------------------------------- -------- ----------------------------
USERNAME    VARCHAR2(30)
SYSDBA      VARCHAR2(5)
SYSOPER     VARCHAR2(5)
SYSASM      VARCHAR2(5)

SQL&gt; 
SQL&gt; select * from v$pwfile_users;

USERNAME                       SYSDB SYSOP SYSAS 
------------------------------ ----- ----- ----- 
SYS                            TRUE TRUE FALSE 
TOM                            TRUE FALSE FALSE

In 11g there is a new column in v$pwfile_users for the SYSASM privilege:
SYS AS SYSDBA @ orcl11 SQL&gt; select * from v$pwfile_users;

USERNAME SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS TRUE TRUE FALSE

For further details see this Tom Kyte article.%3A%3AP11_QUESTION_ID:2659418700346202574&quot;&gt;Here