From: zqzuk <ziqi.zhang@hotmail.com>
To: pgsql-sql@postgresql.org
Subject: nested select within a DISTINCT block
Date: Thu, 14 Sep 2006 05:02:25 -0700 (PDT)
Message-ID: <6304397.post@talk.nabble.com> (raw)
Hi, here i have a problem with this task...
I have a table "cancellation" which stores cancelled bookings and details of
charges etc
and a table "bookings" which stores details of bookings, for example:
cancellation(cancellation_id, booking_id, charge)
booking(booking_id, customer_id, product_package_id, details)
in the query, i wish to find, how many customers have booked for each
product_package_id. if there were 3 bookings for product_package_id=1, and
all these are cancelled and therefore exist in cancellation, then the query
result shoud display something like
package_id, #of bookings
1 0
here are what i tried
select distinct b.product_package_id,
count (distinct b.customer_id and not exists (select cc from cancellation cc
where cc.booking_id=b.booking_id)) from booking as b
group by b.product_package_id
and it doesnt work. the syntax within the DISTINCT is wrong, unsurprisingly.
i also tried
select distinct b.product_package_id,
count (distinct b.customer_id not in (select cc from cancellation cc where
cc.booking_id=b.booking_id)) from booking as b
group by b.product_package_id
it produced incorrect result. ie, for those canceled bookings are also
counted, producing
package_id, #of bookings
1 3
which supposed to be
package_id, #of bookings
1 0
could anyone give any hints please, many thanks !
--
View this message in context: http://www.nabble.com/nested-select-within-a-DISTINCT-block-tf2271181.html#a6304397
Sent from the PostgreSQL - sql forum at Nabble.com.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: ziqi.zhang@hotmail.com
Subject: Re: nested select within a DISTINCT block
In-Reply-To: <6304397.post@talk.nabble.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox