Re: FW: query optimization question

On Wed, 6 Nov 2002 terry(at)ashtonwoodshomes(dot)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 as
select agefunc(dt.days_old_start_date) as ageval,
count(lots.lot_id) as lots from
deficiency_table as dt, lots, deficiency_status as ds
where dt.lot_id = lots.lot_id
and lots.dividion_id=proj.division_id
and lots.project_id=proj.project_id
and dt.deficiency_status_id=ds.deficiency_status_id
and 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,
(select lots 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.