Question

I have two tables, the first (T1) is a base number, the first is a base value per symbol:

symbol       value
------------ -----
ABC           1000
DEF           2000

The second table (T2) s a series of values per date, i.e.:

date         symbol value
----------   ------ -----
2011-09-01   ABC      100
2011-09-02   ABC       10
2011-09-03   ABC        1

What query would I require to get the accumulated total of the value column added to the initial value in the first column over the several days. So the output of the query would look something like

symbol date       total
------ ---------- ------
ABC    2011-09-01   1100
ABC    2011-09-02   1110
ABC    2011-09-03   1111

So its the sum of the inital value in T1 plus the sum of all dates less than the date in that column.

The target database for this is DB2 on iSeries

Answer 1

An SQL approach

select 
   a.symbol, 
   a.value  --current value
     + COALESCE((select sum(value) 
        from T2 b 
        where 
           b.date < a.date and
           b.symbol=a.symbol
        ),0) --sum of history
     + c.value --initial value
from 
   t2 a join t1 c on (a.symbol = c.symbol)