Re: Useful SQL tip for handling optional parameters

<snip>
exec sql
delete from FILE
where FIELD1 = :parm1 and
Field2 = Case When Value2 > '' Then :Parm2 Else Field2;
</snip>

Often times, I use case in the order by and allow null to be returned in
the case. I wonder how this would return if you case both sides.


exec sql
delete from FILE
where FIELD1 = :parm1 and
case when :Parm2 > "" then Field2 end = Case When Parm2

'' Then :Parm2 End;

I'm thinking it would fail because you cannot equate null to null.



On Thu, Dec 8, 2016 at 1:00 AM, Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx>
wrote:

Yet a different solution:

dcl-proc myproc export;
dcl-pi *n;
parm1 char (10) const;
parm2 char (10) const options(*nopass);
end-pi;

dcl-s value2 like(parm2);

if %parms > 1;
value2 = parm2;
endif;

exec sql
delete from FILE
where FIELD1 = :parm1 and
Field2 = Case When Value2 > '' Then :Parm2 Else Field2;



Mit freundlichen Grüßen / Best regards

Birgitta Hauser

"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"
„Train people well enough so they can leave, treat them well enough so they
don't want to.“ (Richard Branson)


-----Ursprüngliche Nachricht-----
Von: RPG400-L [mailto:rpg400-l-bounces@xxxxxxxxxxxx] Im Auftrag von David
Gibbs
Gesendet: Wednesday, 07.12 2016 16:59
An: rpg400-l@xxxxxxxxxxxx
Betreff: Useful SQL tip for handling optional parameters

Folks:

I just had a situation where I needed to handle an optional parameter on a
procedure, where the parameter was being used for record selection in a SQL
statement.

I didn't want to deal with multiple SQL statements based on if the
parameter
was passed or not.

So here's routine I put together ...

dcl-proc myproc export;
dcl-pi *n;
parm1 char (10) const;
parm2 char (10) const options(*nopass);
end-pi;

dcl-s value2 like(parm2);

if %parms > 1;
value2 = parm2;
else;
value2 = '*ALL';
endif;

exec sql
delete from FILE
where FIELD1 = :parm1 and
(FIELD2 = :value2 or :value2 = '*ALL');

end-proc;

I wasn't sure if the ":hostvalue = 'constant'" criteria was going to work,
but it does appear to work fine.

david

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