Set analysis manipulation

[#1]

Hello,

I have a table like that :

items : "id_item,id_item_from,item_value"

where :
- id_item is the item identifiant
- id_item_from represent the id_item of another item (it can be 0 if this item is not linked with an other item)
- item_value is the item value ^^

I need to traverse items which have not a null id_item_from and then :

sums the "item_value" of the items which have an "id_item" who is in the list of "id_item_from"

example :
id_item,id_item_from,item_value
1,0,5
2,0,6
3,1,9
4,2,3



I should have
=> id_item : 3 which have id_item_from = 1 => get the value : 5
=> id_item : 4 which have pour id_item_from = 2 => get the value : 6

Result : 5+6 = 11

I tried this :

Sum({$<id_item={$(=id_item_from)}>} item_value)

It's wrong because "$(=id_item_from)" is the "current" selection ... not the corresponding "id_item_from" of the current traversing "id_item" ...

Any solution ?

Thanks in advance.

[johnw]

Is it OK to handle it in the script? You could join the table back to itself like this:

[Example]:
LOAD * INLINE [
id_item,id_item_from,item_value
1,0,5
2,0,6
3,1,9
4,2,3
];
LEFT JOIN LOAD
id_item as id_item_from
,item_value as item_value_from
RESIDENT [Example]
;