Hey there,
Is this what you are after? Note that I've changed the 'money' type to numeric.
create table testgroupsum (itemname varchar(50),date date,amount numeric);
set datestyle to DMY;
insert into testgroupsum (itemname,date,amount) values ('item
1','2013-01-01','100');
insert into testgroupsum (itemname,date,amount) values ('item
2','2013-01-10','35');
insert into testgroupsum (itemname,date,amount) values ('item
3','2013-02-20','50');
insert into testgroupsum (itemname,date,amount) values ('item
a','2013-01-25','-500');
insert into testgroupsum (itemname,date,amount) values ('item
b','2013-02-28','-20');
SELECT * FROM testgroupsum;
SELECT EXTRACT(month FROM(date)), SUM(amount) FROM testgroupsum GROUP
BY EXTRACT(month FROM(date));
-- Then if you want to put an dollar or whatever you could do this:
SELECT EXTRACT(month FROM(date)), '£' || SUM(amount) FROM testgroupsum
GROUP BY EXTRACT(month FROM(date));
DROP TABLE testgroupsum;
Regards
James
On 10 September 2013 10:02, e-letter <inpost@gmail.com> wrote:
> Readers
>
> How to apply a sum function to rows grouped by date?
>
> create table testgroupsum (itemname varchar(50),date date,amount money);
> set datestyle to DMY;
> insert into testgroupsum (itemname,date,amount) values ('item
> 1','2013-01-01','100');
> insert into testgroupsum (itemname,date,amount) values ('item
> 2','2013-01-10','35');
> insert into testgroupsum (itemname,date,amount) values ('item
> 3','2013-02-20','50');
> insert into testgroupsum (itemname,date,amount) values ('item
> a','2013-01-25','-500');
> insert into testgroupsum (itemname,date,amount) values ('item
> b','2013-02-28','-20');
> drop table testgroupsum;
>
> How to change currency unit for the data type money, i.e. to change
> the currency sign from dollar ($) shown in a query result?
>
> The manual states that date data can be extracted, so the following was tried:
>
> select extract (month from (select date from testgroupsum where date >
> '2013-01-01'));
> ERROR: more than one row returned by a subquery used as an expression
>
> The objective is to be able to apply sum function to items 1 and 2,
> grouped by month value = 1. Then to apply a subsequent _net_ sum 1
> items 1 and 2, item a, i.e. for month value = 1, compute sum
> 100,35,-500; month value = 2, compute sum 50,-20; etc.
>
> Thanks in advance.
>
>
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