Re: Tabulate data incrementally - Mailing list pgsql-general

From Omar Eljumaily
Subject Re: Tabulate data incrementally
Date
Msg-id 45F03C66.50806@omnicode.com
Whole thread Raw
In response to Re: Tabulate data incrementally  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Tabulate data incrementally  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-general
Thanks Tom and Richard for the tip on date_trunc.  Is it possible in an
sql select statement to create an iterator?

For instance

select myItFunc(1,10);

would give 1,2,3,4,5,6,7,8,9,10

I'm a bit embarrassed that I don't know how to do this.  My
understanding of sql functions is that not being object oriented, they
don't store state.

The reason I'm asking is that if I wanted to to use date_trunc, I think
I would need some sort of iterator to get multiple rows in one statement.

What I'm looking for is:

Employee Week   Amount
John            1/1      100
Mary            1/1     0
Edward      1/2      100
etc

I'd also like to return zero or null values when the data doesn't
exist.  Wouldn't I need an iterator to do that?

Thanks,

Omar


Tom Lane wrote:
> Omar Eljumaily <omar2@omnicode.com> writes:
>
>> I want to tabulate time data on a weekly basis, but my data is entered
>> on a daily basis.
>>
>
> Something involving GROUP BY date_trunc('week', _date) might work for
> you, if your definition of week boundaries matches date_trunc's.
> If not, you could probably make a custom function that breaks at the
> boundaries you want.
>
>             regards, tom lane
>
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