SQL> select * from dept order by deptno;

    DEPTNO DNAME          LOC
---------- -------------- -------------
         0 ss             tt
         0 smlee          insert
         1 tt             ii
         1 tt             uu
         2 yy             gg

SQL> break on deptno
SQL> select * from dept order by deptno;

    DEPTNO DNAME          LOC
---------- -------------- -------------
         0 ss             tt
           smlee          insert
         1 tt             ii
           tt             uu
         2 yy             gg