Here is a simple tips to find oracle SID with/without SYSDBA privilege.
To get oracle SID without SYS_DBA priviledge:
select sys_context('userenv','instance_name') from dual;
To get database name
select sys_context('userenv','db_name') from dual;
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To get oracle SID without SYS_DBA priviledge:
select sys_context('userenv','instance_name') from dual;
To get database name
select sys_context('userenv','db_name') from dual;
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