a subquery returns a null column when the subquery returns zero rows:
select srcdta,
( select ibmreqd from sysibm/sysdummy1
where ibmreqd = 'N' ) ibmreqd
from qrpglesrc
but replace the subquery with lateral and the outer query returns nothing
if the lateral returns zero rows. Like the lateral is considered a join and
not a left outer join. Is that correct? Can lateral be made to behave like
a left outer join?
( I want to use lateral because lateral supports "fetch first row only" )
select a.srcdta, b.ibmreqd
from qrpglesrc a
, lateral ( select c.ibmreqd from sysibm/sysdummy1 c
where c.ibmreqd = 'N' ) b
