Как правильно присвоить переменной значение из таблицы

create or replace trigger TR_DOC_CONTENT_AU
  after update on doc_content  
  for each row
declare
  -- local variables here
   v_username varchar2(50);
begin

    -- Find username of person performing UPDATE into table
    SELECT Terminal  from v$session INTO v_username
      where sid=(select sid from v$mystat where rownum=1);

    -- Insert record into audit table
    INSERT INTO log_doc_edit
     ( ID,
       TYPE,      
       comp_name ,
       doc_id ,
       log_date )
    VALUES
     ( SEQ_LOG_DOC_EDIT_ID.NEXTVAL,
       1,
       v_username,      
       :NEW.doc_id,
       SYSDATE
     );
  
  
end TR_DOC_CONTENT_AU;

1) select ...
2) INTO ...
3) from ...