Re: Using host variables in SQLRPGLE doesn't seem to be working....INclause

[CRPence <CRPbottle@xxxxxxxxx>]

On 1/10/11 12:57 PM, Bryce Martin wrote:
> Won't the multiple select statement have a negative impact on
> performance compared to a list of predetermined values?
>
> "Schutte, Michael Don01/10/2011 03:36 PM wrote:
> > Change this to...
> >
> > Select Cast(rncust As Numeric(6,0)),
> >         Cast(rnseq As Numeric(4,0)),
> >         Cast(rntype As Numeric(2,0)),
> >         rnword1, rnword2, rnword3, rnword4, rnword5
> >    From rcm002pf
> > Where rnword1 in  (select WorkKey1 from WorkTable1)

  The real issue for performance impact would be for the /maintenance/ 
on the work table [i.e. drop, create, open, insert, clear...] rather 
than the much smaller impact of running and using the result of the 
subselect.  If the input string is as easily parsed as the example, then 
I believe a recursive CTE breaking the string into rows [of a true 
temporary file as created by the database scoped to that SELECT] would 
perform noticeably faster than using a user-created work table.

Regards, Chuck