Question:
I need to do a cumulative sum, with the last column updated record-by-record, in a report.
Something like this:
+-------+----+---------+
| stage | km | cum. km |
+-------+----+---------+
| 1 | 5 | 5 |
| 2 | 7 | 12 |
| 3 | 9 | 21 |
| 4 | 5 | 26 |
+-------+----+---------+
Answer:
- Modify SQL query to select km field twice i.e.
select ...
km,
km as cumkm
from ...
2. Set 'View as' type of cumkm to Custom and use the following code:
$_SESSION["cumkm"]+=$value;
$value=$_SESSION["cumkm"];
3. Add BeforeProcessList event to reset the value of $_SESSION["cumkm"]
$_SESSION["cumkm"]=0;