Re: FW: query optimization question

On Wed, 6 Nov 2002 terry@ashtonwoodshomes.com wrote:

> However, for the total deficiencies I am then splitting up the total into
> aging groups, eg <30, 30-60, 60-90, and >90 days old.  The query for that
> looks like the below.  But before I paste it in, I would like to optimize
> it, if I could do so with a group by clause I most certainly would, but I
> don't see how I can BECAUSE OF THE AGING BREAKDOWN:

Well, as a first step, I'd suggest using an age function as already
suggested and a temporary table to hold the grouped by values temporarily
and then doing the subselects against that.

Maybe something like (untested):
create temp table defs asselect agefunc(dt.days_old_start_date) as ageval, count(lots.lot_id) as lots from
deficiency_tableas dt, lots, deficiency_status as ds where dt.lot_id = lots.lot_id and
lots.dividion_id=proj.division_idand lots.project_id=proj.project_id and
dt.deficiency_status_id=ds.deficiency_status_idand ts.is_outstanding and dt.assigned_supplier_id='101690'group by
ageval;

-- same general thing for other repeated queries

select project_id, marketing_name,(select sum(lots) from defs) as def_count,(select lots from defs where ageval=0) as
def_count_less_30,(selectlots from defs where ageval=1) as def_count_30_60,...
 

Since you want 0's instead of nulls, you'd probably need to do
a coalesce for the subselects, and this will go through the
probably 5 or so line temp table rather than the presumably large
other table.

I haven't spent much thought trying to force it down into a
single query, but that seems a bit harder.