Re: Help : Sum 2 tables based on key from other table - Mailing list pgsql-general

If the tables aren't huge, you're not concerned about optimization, and you just want to get your numbers, I think something like this would do the trick.  I haven't actually tried it 'cause I didn't have easy access to your tables:

SELECT 

  a.product_id,

  a.product_name,

  b.initial_stock_sum,

  c.in_out_sum,

  c.in_sum,

  c.out_sum

FROM

  a

LEFT JOIN

  (SELECT

    product_id,

    SUM(initial_stock) AS initial_stock_sum

  FROM b

  GROUP BY product_id

  ) b USING (product_id)

LEFT JOIN

  (SELECT

    product_id,

    sum(CASE WHEN date < 'BEGINNING DATE' THEN in-out ELSE 0 END) AS in_out_sum,

    sum(CASE WHEN date BETWEEN 'BEGINNING DATE' AND 'ENDING DATE' THEN in ELSE 0 END) AS in_sum,

    sum(CASE WHEN date BETWEEN 'BEGINNING DATE' AND 'ENDING DATE' THEN out ELSE 0 END) AS out_sum

   FROM c

   GROUP BY product_id

   ) c USING (product_id)

WHERE a.supplier_id='XXX';

Cheers,

Ken

On Mon, Nov 18, 2013 at 12:47 AM, Raymond O'Donnell <rod@iol.ie> wrote:

On 18/11/2013 02:16, Hengky Liwandouw wrote:

> Dear Friends,
>
> Please help for the select command, as i had tried many times and
> always can not display the result as what i want.
>
> I am looking for the solution on google but still can not found the
> right answer to solve the problem.
>
> I have 3 tables :
>
> Table A ProductID ProductName SupplierID
>
> Table B ProductID InitialStock
>
> Table C ProductID Date In Out
>
> 1. I want to select all productID from Table A where
> supplierID='XXX'.
>
> 2. Based on list from Step.1 : sum the initialstock from  Table B
>
> 3. Based on list from Step 1 : Sum (in-out) from Table C where date
> <'BEGINNING DATE'
>
> 4. Based on list from Step 1 : Sum (in) and sum(out) from Table C
> where date between 'BEGINNING DATE' and 'ENDING DATE'
>
> So the result will look like this :
>
> ProductID  ProductName  SumofIntialStock  sum(in-Out)<beginningdate
> SumofIN  SumofOut xxxx           xxxxxxxxxxxxx              99
> 99                                 99             99 xxxx
> xxxxxxxxxxxxx              99                               99
> 99             99 xxxx           xxxxxxxxxxxxx              99
> 99                                 99             99 xxxx
> xxxxxxxxxxxxx              99                               99
> 99             99

You could try using common table expressions, which let you build up to
your final result in steps. Some reading:

http://www.postgresql.org/docs/9.3/static/queries-with.html

http://www.chesnok.com/daily/2013/11/12/how-i-write-queries-using-psql-ctes/


Ray.


--
Raymond O'Donnell :: Galway :: Ireland
rod@iol.ie

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