Hello,
I save values in some tables (simpler description)
First a Table who saved the timestamp of the mensuration
Table A timestamps
ID primary key
TS timestamp
Second a Table with the measured data (25 records/measured sensors will be
saved every 10 Minutes, one record in Table A, 25 in Table B)
Table B mensuration
ID primary key
ID_counter integer of item to measure
ID_Timestamp foreign key of Table A
Value (double precision)
Now I would like to make an analysis. At the time, I do this:
for select cast(ts as date) as mz from tablea where ts >= "criteria from"
and ts < "criteria to"
group by mz)
into :messzeit do
begin
f_messwert = null;
MESSWERTE = '';
for select a.id_counter, sum(a.value) from tableb a left join tablea b
on a.id_timestamp = b.id
where cast(b.ts as date) = :messzeit
group by a.id_counter
into :i_zae, :f_messwert do
begin
if(f_messwert is null) then f_messwert = 0;
MESSWERTE = MESSWERTE || cast(:i_zae as varchar(4)) || '=' ||
cast(:f_messwert as varchar(8)) || ';';
end
suspend;
end
The Result is one returned record for each day (day, conter 1 = 123; counter
2 = 222;.)
It takes a long time but I must integrate the tablea on the second part of
the statement. How can I optimize this in firebird?
Thank you
Regards
Olaf
