join with sum

[Cam Bazz]

Hello,

Lets say I have two tables like

A:
1,11
2,15

and

B:
1,10
4,11
5,10

and joinin them

J = JOIN A by $0 FULL, B by $0

I get J:

1,11,1,21
2,16,,
,,4,11
,,5,10

which is a full outer join:

what I need is:

1,31
2,16
4,11
5,10

so I want to join by key, and then sum some fields.

the regular sum operator is for group or agregate summing and can not do it.

any ideas / recomendation / help greatly appreciated.

best.
c.b.