Running Sum without analytic function

Question

Hi
I have data like below
Create table Test (Name Varchar(30),M Int, Y Int, Val Int);
Insert into Test Values ('A',1,2011,2);
Insert into Test Values ('A',2,2011,2);
Insert into Test Values ('A',3,2011,2);
Insert into Test Values ('A',4,2011,2);
Insert into Test Values ('A',5,2011,2);
Insert into Test Values ('A',6,2011,2);
Insert into Test Values ('A',7,2011,2);
Insert into Test Values ('A',8,2011,2);
Insert into Test Values ('A',9,2011,2);
Insert into Test Values ('A',10,2011,2);
Insert into Test Values ('A',11,2011,2);
Insert into Test Values ('A',12,2011,2);
Insert into Test Values ('A',1,2012,2);
Insert into Test Values ('A',2,2012,2);
Insert into Test Values ('A',3,2012,2);
Insert into Test Values ('A',4,2012,2);
Insert into Test Values ('A',5,2012,2);
Insert into Test Values ('A',6,2012,2);
Insert into Test Values ('A',7,2012,2);
Now based on above data I need to calculate running sum for past 18 Months. Condition is I can not use analytic function or Oracle specific SQL functions (for portability).
I tries following SQL but it dint work
select Name,rnk, SUM(val) from (
SELECT a.Name,a.m,a.Y,b.val, count(*) rnk
from Test a, Test b
where (a.Name=b.Name and (a.M <= b.M and a.Y<= b.Y))
group by a.Name,a.Y,a.m
order by a.Name,a.Y,a.m
) abc
group By Name,rnk
Order by Name,rnk
Can some one give suggastion.

Answer 1

Hi,
I don't see what your query or your desired results have to do with the last 18 months. Is the task here to show for a given month (July, 2012, for example) the total of the 18 months ending in that month (February, 2011 through July, 2012 in this case) for the same name? If so:
SELECT       c.name, c.y, c.m
,       SUM (p.val)     AS running_total
FROM       test     c
JOIN       test     p  ON     ( ((12 * c.y) + c.m)
               - ((12 * p.y) + p.m)
               ) BETWEEN 0 AND 17
GROUP BY  c.name, c.y, c.m
ORDER BY  c.name, c.y, c.m
;Output:
NAME                Y          M RUNNING_TOTAL
A                2011          1             2
A                2011          2             4
A                2011          3             6
A                2011          4             8
A                2011          5            10
A                2011          6            12
A                2011          7            14
A                2011          8            16
A                2011          9            18
A                2011         10            20
A                2011         11            22
A                2011         12            24
A                2012          1            26
A                2012          2            28
A                2012          3            30
A                2012          4            32
A                2012          5            34
A                2012          6            36
A                2012          7            36