Re: SELECT with sum on groups ORDERING by the subtotals

I think it will be better to add one more column for subtotal and
write an "on before insert" trigger to update the subtotal with sum of
total.


with regards,
S.Gnanavel


> -----Original Message-----
> From: grupos@carvalhaes.net
> Sent: Thu, 16 Jun 2005 00:56:42 -0300
> To: pgsql-sql@postgresql.org
> Subject: [SQL] SELECT with sum on groups ORDERING by the subtotals
>
> Hi Guys!
>
> I need to make a complex query. I am thinking to use plpgsql BUT I am
> confused how I can solve this.
>
> What I have:
> CREATE TABLE test
> (
>   code varchar(15),
>   description varchar(60),
>   group varchar(10),
>   quant float8,
>   price float8,
>   total float8
> )
> WITHOUT OIDS;
>
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92110', 'PRODUCT A', 10, 1, 10);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92110', 'PRODUCT A', 5, 0.90, 9);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92110', 'PRODUCT A', 100, 0.9, 90);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92110', 'PRODUCT A', 10, 1.1, 11);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92190', 'PRODUCT b', 10, 1.1, 11);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92190', 'PRODUCT b', 10, 1.1, 11);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92190', 'PRODUCT b', 10, 1.1, 11);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('92190', 'PRODUCT b', 20, 0.8, 8);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('99120', 'PRODUCT C', 10, 0.8, 8);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('99120', 'PRODUCT C', 100, 0.8, 80);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('99120', 'PRODUCT C', 200, 0.8, 160);
> INSERT INTO test (code, description, quant, price, total) VALUES
> ('99120', 'PRODUCT C', 100, 0.9, 90);
>
>
> I need an subtotal for all the products with the same group and that the
> query be ordered by the bigger subtotal.
>
> For example, I need an output like this:
> Ex.
>
>
>  code  | description | quant | price | total | subtotal
> -------+-------------+-------+-------+-------+----------
>  99120 | PRODUCT C   |    10 |   0.8  |     8  |      8
>  99120 | PRODUCT C   |   100 |   0.8 |    80 |      88
>  99120 | PRODUCT C   |   200 |   0.8 |   160|      168
>  99120 | PRODUCT C   |   100 |   0.9 |    90 |      667
>  92110 | PRODUCT A   |    10 |     1   |    10 |       10
>  92110 | PRODUCT A   |     5 |   0.9   |     9  |       19
>  92110 | PRODUCT A   |   100 |   0.9 |    90 |      109
>  92110 | PRODUCT A   |    10 |   1.1  |    11 |      120
>  92190 | PRODUCT b   |    10 |   1.1   |    11 |      11
>  92190 | PRODUCT b   |    10 |   1.1   |    11 |      22
>  92190 | PRODUCT b   |    10 |   1.1   |    11 |      33
>  92190 | PRODUCT b   |    20 |   0.8   |     8  |      41
>
> The subtotal column must sum all the products with the same code and put
> the result in order of the bigger sultotals.
>
> Only make a function that sum the last value + the subtotal it's not
> hard BUT how I can make the subtotal restart when the code changes and
> how I will order the result by the bigger subtotal code groups?
>
> Thanks!
>
> Rodrigo Carvalhaes
>
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