Subject Re: [firebird-support] PSQL: Getting both aggregation and individual rows
Author Josef Kokeš

I tried this approach before, but it violates my "only run GET_DATA
once" requirement :-(


On 21.10.2014 21:15, Svein Erling Tysvær
svein.erling.tysvaer@... [firebird-support] wrote:
> What about
> FOR WITH TMP(MyDateTime, MySum) as
> (SELECT MIN(dateandtime), SUM(Value)
> FROM gen_data(...))
> SELECT,, g.dateandtime, g.value, t.MyDateTime, tMySum
> FROM gen_data(...) g
> CROSS JOIN tmp t
> Of course, you may want a different join to CROSS JOIN.
> HTH,
> Set
> ________________________________________
> Fra: []
> Sendt: 21. oktober 2014 09:39
> Til: Firebird Support
> Emne: [firebird-support] PSQL: Getting both aggregation and individual rows
> Hi!
> Is there a simple way to get an aggregation of some query as well as the
> individual rows from within a PSQL? I.e., I have a stored procedure
> GEN_DATA which produces individual rows (ID, Name, DateAndTime, Value).
> I am processing the output of GEN_DATA in another stored procedure
> FOR SELECT id, name, dateandtime, value
> FROM gen_data(...)
> INTO ...
> DO ...
> Within this loop, I need the individual records, but I also need some
> aggregations on them, i.e. MIN(dateandtime) or SUM(value). If I could
> run GEN_DATA twice, then it would be easy (in the first run I would
> calculate the aggregations, in the second run the individual values),
> but I can't. If I could perform the processing in my application (rather
> than the stored procedure), it would be easy, too (I would simply
> traverse the result dataset of GEN_DATA twice), but again I can't do
> that. Would Common Table Expressions or perhaps Derived Tables help me?
> Thanks,
> Josef