The times listed are what it takes to run each query separately. If I
run it as one query, I kill it after several minutes.
The plan is natural for all querys. The only thing I can think of is
that FB is evaluating the IN statement for every row.

-- 0.781s
select

di2.ID,di2.NDC,di2.FRMTD_NDC,di2.UPC_HRI,di2.FRMTD_MDDB_UPC_HRI,di2.GPI,
di2.STATUS,di2.NAME,di2.LABELNAME
from
MDDB_DRUGITEM di2
where
di2.NDC in
(
-- 0.561s
select
d1.ndc
from
mddb_drugitem d1
where
d1.upc_hri is not null and d1.ndc is not null
group by
d1.ndc
having
count(*) > 1
)