Correlated Subquery and calculated column non-functional
Hi Everyone,
I am having an issue with a query that I thought would be a fairly
simple matter to implement, but apparently I have done something
wrong. Can anyone point me in the right direction for a solution and
explain where I have made my mistake? The idea is to produce a rank
value for each row in the resultset.
This is the query:
select
product.manufacturer,
product.brand,
SUM(sales.qtysold * sales.unitprice) as turnover,
(select count(*) from cube_sales.sales as Q WHERE SUM(sales.qtysold *
sales.unitprice) > turnover) + 1 as rank
from
cube_sales.sales INNER JOIN
cube_sales.product ON
sales.productid = product.productid
group by
product.manufacturer,
product.brand;
I am receiving a : column "turnover" does not exist
SQL state: 42703
Character: 155
I understand that there is some difference with subselects in Postgres
vs MySQL or Oracle for example, but I am out of my depth on this one.
Can anyone help?
The Frog
On 30/10/2009 10:07, The Frog wrote:
select
product.manufacturer,
product.brand,
SUM(sales.qtysold * sales.unitprice) as turnover,
(select count(*) from cube_sales.sales as Q WHERE SUM(sales.qtysold *
sales.unitprice) > turnover) + 1 as rank
You can't use the alias "turnover" in the calculation as you have - you
need to use the full expression instead, or push the calculation into a
subquery.
BTW you're also missing a closing parenthesis from that calculation.
Ray.
--
Raymond O'Donnell :: Galway :: Ireland
rod@iol.ie
On Fri, Oct 30, 2009 at 10:42 AM, Raymond O'Donnell <rod@iol.ie> wrote:
On 30/10/2009 10:07, The Frog wrote:
select
product.manufacturer,
product.brand,
SUM(sales.qtysold * sales.unitprice) as turnover,
(select count(*) from cube_sales.sales as Q WHERE SUM(sales.qtysold *
sales.unitprice) > turnover) + 1 as rankYou can't use the alias "turnover" in the calculation as you have - you
need to use the full expression instead, or push the calculation into a
subquery.BTW you're also missing a closing parenthesis from that calculation.
Also you can't use aggregate functions in the WHERE clause. You'll
need to push it down to the HAVING clause.
--
Regards,
Richard Broersma Jr.
Visit the Los Angeles PostgreSQL Users Group (LAPUG)
http://pugs.postgresql.org/lapug
The Frog wrote on 30.10.2009 11:07:
select
product.manufacturer,
product.brand,
SUM(sales.qtysold * sales.unitprice) as turnover,
(select count(*) from cube_sales.sales as Q WHERE SUM(sales.qtysold *
sales.unitprice) > turnover) + 1 as rank
from
cube_sales.sales INNER JOIN
cube_sales.product ON
sales.productid = product.productid
group by
product.manufacturer,
product.brand;I am receiving a : column "turnover" does not exist
SQL state: 42703
Character: 155I understand that there is some difference with subselects in Postgres
vs MySQL or Oracle for example, but I am out of my depth on this one.Can anyone help?
You can't use a column alias as reference for other expressions inside the same statement (I don't think that is different in Oracle or MySQL)
Btw: your statement will be horribly in-efficient as the select count(*) will be execute for *every* row from the main query.
If I understand your statement correctly, you can get rid of the "sub-select" completely with Postgres 8.4
SELECT product.manufacturer,
product.brand,
SUM(sales.qtysold * sales.unitprice) as turnover,
rank() over (partition by manufacturer, brand order by SUM(sales.qtysold * sales.unitprice)) as rank
FROM cube_sales.sales
INNER JOIN cube_sales.product ON sales.productid = product.productid
GROUP BY product.manufacturer,
product.brand;
(Not tested)
Thomas