create table test_leiji(rpt_month_id number(8),

                        current_month NUMBER(12,2));

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (200901, 380128.344363);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (200902, 274474.595772);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (200903, 309427.898521);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (200904, 379854.833875);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (201001, 380128.344363);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (201002, 274474.595772);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (201003, 309427.898521);

insert into test_leiji (RPT_MONTH_ID, CURRENT_MONTH) values (201004, 379854.833875);

select  * from  test_leiji t

SELECT rpt_month_id,

       current_month,

       SUM (current_month) OVER (PARTITION BY SUBSTR (rpt_month_id, 1, 4)order by rpt_month_id) sum_month

  FROM test_leiji

  order by rpt_month_id;

显示结果如图：