On Mon, 15 Dec 2014 16:01:27 +0100, "'checkmail' check_m...@satron.de [firebird-support]" <firebird-support@yahoogroups.com> wrote: > 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?
That is not surprising. You are executing a query and for each row you are executing another query. Use joins and/or subqueries instead. Mark
