programming in pgsql

Hi Pgsql,

Could anyone please advise whether the following program can be implemented
using pgsql cursors/anythign else (or do we need some external scripts)?If
yes, could you give please some function names etc?

select A from Bcluster where pvalue = 0.3
--say we get A=8
select B, A_child from CCluster where A = 8
--If we get a A_child (say we get A_child=7) from the above query we search
that value in CCluster table again and store the Bs in some place as:
select B, A_child from CCluster where A = 7
--We do this till we get all Bs and no more A_childs
--We display and store the Bs for further usage

Thanks,
AK