DB2 7.2 ZOS col to row after query

[ebaccini]

Hi,
I've a query from 2 tables that give me a table like this as an answer:

select a.COL1, a.COL2, a.COL3, a.COL4,  b.COL5 from db2.tb1 a, db2.tb2 b where  a.COL1 = b.COL1 and  a.COL1 = "VAL1"

COL1     COL2     COL3     COL4     COL5
VAL1     VAL2     VAL3     VAL4     PRB1
VAL1     VAL2     VAL3     VAL4     PRB2

And due to the fact that this query is the base to populate a grid with this data I want to present my result in this other way:

COL1     COL2     COL3     COL4     COL5
VAL1     VAL2     VAL3     VAL4     PRB1,PRB2

maybe I'm just stupid but I had a lot of difficulties in implement recursive queries and the DB2 version we got does not support XML nor LISTAGG.

Any suggestion?

Thanks in advance
Emiliano