I'm confused.
It seems that you are after those rows from myfile where they exist in an empty result set? I don't get it.
There is no way that field2 can exist in a null result set, because a NULL result set is, well, null.
A little more definition of your goals would help.
Steve Needles
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of John Yeung
Sent: Friday, August 04, 2017 1:46 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Subject: Idiomatic SQL empty set?
Is there an idiomatic, or at least common, expression that returns the empty set in DB2 for i? (Or is that Db2 for i now?)
For example, maybe something like
select * from sysibm.sysdummy1 where 1 > 2
In particular, I'm interested in an expression that can be used with IN, as in
select myfield1 from mylib.myfile where myfield2 in (emptyset)
I was really hoping that it would simply be (), but that doesn't work.
So for now, the larger statement looks like
select myfield1 from mylib.myfile
where myfield2 in (select * from sysibm.sysdummy1 where 1 > 2)
Surely there's something better?
(In case you haven't guessed, the set of desired values for myfield2 is dynamically generated and won't always be empty.)
John Y.
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