Treating result of subselect as row

Hi,

 

If I have a subselect that returns one row, then how can I use this in expressions that expects row constructors in the operands, like OVERLAPS or IN ?

 

SELECT (subselect1) OVEPLAPS (subselect2)   -- both subselect returns one row and two columns

 

OR:

 

SELECT (SubselectWithOneRow) IN (subselect2)   -- but here subselect2 may return many rows, but column counts are equal

 

I tried these in 8.2 without success.

 

Thanks,

Otto