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* recommending change to first example in 7.8.1
@ 2017-07-24 21:50 ruth@dannerdata.com
0 siblings, 1 reply; 2+ messages in thread
From: ruth@dannerdata.com @ 2017-07-24 21:50 UTC (permalink / raw)
To: pgsql-docs
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/9.6/static/queries-with.html
Description:
The first example in 7.8.1 shown below includes a field called 'quantity' to
be summed in the primary SELECT statement. I think this is a mistake. I do
not think this field exists in the WITH virtual table.
7.8.1. SELECT in WITH
The basic value of SELECT in WITH is to break down complicated queries into
simpler parts. An example is:
WITH regional_sales AS (
SELECT region, SUM(amount) AS total_sales
FROM orders
GROUP BY region
), top_regions AS (
SELECT region
FROM regional_sales
WHERE total_sales > (SELECT SUM(total_sales)/10 FROM
regional_sales)
)
SELECT region,
product,
SUM(quantity) AS product_units,
SUM(amount) AS product_sales
FROM orders
WHERE region IN (SELECT region FROM top_regions)
GROUP BY region, product;
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^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: recommending change to first example in 7.8.1
@ 2017-07-25 22:27 David G. Johnston <david.g.johnston@gmail.com>
parent: ruth@dannerdata.com
0 siblings, 0 replies; 2+ messages in thread
From: David G. Johnston @ 2017-07-25 22:27 UTC (permalink / raw)
To: ruth@dannerdata.com <ruth@dannerdata.com>; +Cc: pgsql-docs
On Monday, July 24, 2017, <ruth@dannerdata.com> wrote:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/9.6/static/queries-with.html
> Description:
>
> The first example in 7.8.1 shown below includes a field called
> 'quantity' to
> be summed in the primary SELECT statement. I think this is a mistake.
It isn't.
> I do
> not think this field exists in the WITH virtual table
>
It wouldn't matter if it did since in the main query the only from item is
the orders table which can be reasonably assumed to contain a quantity
column.
David J.
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