I'm doing a rather complicated bit of SQL involving summing various bits
from several tables into memory tables, adding/subtracting from these into
new memory tables, and then picking them all up in a final query which I
show in a grid.

When I added a 4th LEFT OUTER JOIN from a memory table to the final query
(after dropping the no-longer-needed intermediate tables), its values were
not used (i.e. were NULL) until I moved its LEFT OUTER JOIN line up to the
top, whereupon two other joined tables gave NULL values after having
initially given the expected values.

I got around this by doing some more summing into intermediate tables
higher up and only using three joins from memory tables in the final query.

Is this normal behaviour?

Can I change a parameter to increase the number of joins in a single query?

--
Chris

Chris,

<< When I added a 4th LEFT OUTER JOIN from a memory table to the final query
(after dropping the no-longer-needed intermediate tables), its values were
not used (i.e. were NULL) until I moved its LEFT OUTER JOIN line up to the
top, whereupon two other joined tables gave NULL values after having
initially given the expected values.

I got around this by doing some more summing into intermediate tables
higher up and only using three joins from memory tables in the final query.

Is this normal behaviour? >>

I really couldn't say without seeing and running the actual queries to see
if they are indeed performing as required.  Also, is this 4.24 B1, or an
earlier version ?

--
Tim Young
Elevate Software
www.elevatesoft.com

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in
news:CED2A32F-1815-41F1-BAB0-CEB4D5AD0BBF@news.elevatesoft.com:

>  Is this normal behaviour? >>
>
> I really couldn't say without seeing and running the actual queries to
> see if they are indeed performing as required.

Thanks for responding, Tim. I really only wanted to know if DBISAM has a
limit on the number of LEFT OUTER JOINs or "\memory\.." tables one can
use in a given script, so if there isn't one I'm probably responsible,
and my workaround is sufficient for now.

I don't think it's worth losing any sleep over - we both seem to have
plenty of other stuff to keep us busy

>  Also, is this 4.24 B1,
> or an earlier version ?

See my new signature - I've just discovered I can personalise my
signatures for each news server in XNews


--
Chris
(XP-Pro + Delphi 7 Architect + DBISAM 4.24 Build 1)

Chris,

<< See my new signature - I've just discovered I can personalise my
signatures for each news server in XNews  >>

Cool.

--
Tim Young
Elevate Software
www.elevatesoft.com