Hi,
In my table below, I am trying to solve this issue for the value of KEY1. So for all IDs belonging to the same KEY3 (for e.g. IDs:1,2,3 all belong to KEY3: A), the value of KEY1, where KEY2 = X, should be the sum of all KEY1 values belonging to the same KEY3 (for e.g. KEY1s:200,300,500 all belong to KEY3: A). I've added another table below to show what the result should look like.
| ID | KEY1 | KEY2 | KEY3 |
| 1 | 200 | | A |
| 2 | 300 | X | A |
| 3 | 500 | | A |
| 4 | 800 | X | B |
| 5 | 100 | | B |
| 6 | 700 | | C |
| 7 | 400 | | C |
| 8 | 600 | X | C |
| 9 | 200 | | D |
This is what the result should look like (change in KEY1 values, where KEY2 = X):
| ID | KEY1 | KEY2 | KEY3 |
| 1 | 200 | | A |
| 2 | 1000 | X | A |
| 3 | 500 | | A |
| 4 | 900 | X | B |
| 5 | 100 | | B |
| 6 | 700 | | C |
| 7 | 400 | | C |
| 8 | 1700 | X | C |
| 9 | 200 | | D |
Thank you! Much appreciated!