Re: help me...

The world rejoiced as ron_tabada(at)yahoo(dot)com (ron_tabada) wrote:
> Hello everyone, Good day! Could anyone help me translate this query
> in Microsoft Access to Postgresql. I'm having a difficulty. Pls...
>
> Query1:
> SELECT items.description, Sum(supplieditems.qty) AS SumOfqty
> FROM items INNER JOIN supplieditems ON items.itemno = supplieditems.itemno
> GROUP BY items.description;
>
> Query2:
> SELECT [items].[description], Sum([customer].[qty]) AS SumOfqty
> FROM (items INNER JOIN OtherItem ON [items].[itemno]=[OtherItem].[Itemno]) INNER JOIN customer ON
> [OtherItem].[Itemno]=[customer].[itemcode]
> GROUP BY [items].[description];
>
> Query3:
> SELECT [Query1].[SumOfqty], [Query2].[SumOfqty], [Query1]![SumOfqty]-[Query2]![SumOfqty] AS remain
> FROM Query1, Query2;
>
> I have translated Query1 and Query2 in POSTGRESQL but I don't know
> how to implement Query3.

Apparently you have discovered the nearest equivalent to "VIEWs" in
Access.

I can suggest two ways:

1. Define "query1" and "query2" as PostgreSQL views, as with...

create view query1 as
SELECT items.description, Sum(supplieditems.qty) AS SumOfqty
FROM items INNER JOIN supplieditems ON items.itemno = supplieditems.itemno
GROUP BY items.description;

create view query2 as [omitted details].

Query 3 should work perfectly well when it has the two views to work
with.

2. Subselects...

SELECT Query1.SumOfqty, Query2.SumOfqty, Query1.SumOfqty-Query2.SumOfqty AS remain
FROM
(select stuff for query 1) as query1,
(select stuff for query 2) as query2;

Approach #1. seems more appropriate, as it uses the views to keep the
queries all simple.
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