From: Julie Robinson <funkjunk@bellsouth.net>
To: pgsql-sql@postgresql.org
Subject: Re: SQL Query Newbie Help
Date: Fri, 24 Mar 2006 11:50:57 -0600
Message-ID: <1228cchdf3qqfe@corp.supernews.com> (raw)
In-Reply-To: <12287b48nref60f@corp.supernews.com>
References: <12287b48nref60f@corp.supernews.com>
This works, but is there a better solution?
select *
from quality_control_reset T
where date = (
select max(date)
from quality_control_reset
where qualitycontrolrange = T.qualitycontrolrange);
Julie Robinson wrote:
> Given the two tables at the bottom of this email, I'm having trouble
> coming up with a SQL statement that returns all rows in the
> quality_control_reset table where there is only one row for the most
> recent quality_control_range. Help?
>
> Example:
>
> In table quality_control_reset:
>
> id | date | qualitycontrolrange
> ---------------------------------------------
> 1 | 02/23/2006 | 20
> 2 | 02/23/2006 | 6
> 3 | 02/28/2006 | 18
> 4 | 03/01/2006 | 18
> 5 | 03/23/2006 | 12
> 6 | 03/23/2006 | 20
>
> I want the results of the following from the query:
>
> id | date | qualitycontrolrange
> ---------------------------------------------
> 2 | 02/23/2006 | 6
> 4 | 03/01/2006 | 18
> 5 | 03/23/2006 | 12
> 6 | 03/23/2006 | 20
>
>
> CREATE TABLE quality_control_reset
> (
> id int8 NOT NULL,
> date timestamp,
> qualitycontrolrange int8,
> CONSTRAINT quality_control_reset_pkey PRIMARY KEY (id),
> CONSTRAINT fk42a706efb62efa94 FOREIGN KEY (qualitycontrolrange)
> REFERENCES quality_control_range (id) MATCH SIMPLE
> ON UPDATE NO ACTION ON DELETE NO ACTION
> )
>
> CREATE TABLE quality_control_range (
> id int8 NOT NULL,
> code varchar(255),
> CONSTRAINT quality_control_range_pkey PRIMARY KEY (id)
> );
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To: pgsql-sql@postgresql.org
Cc: funkjunk@bellsouth.net
Subject: Re: SQL Query Newbie Help
In-Reply-To: <1228cchdf3qqfe@corp.supernews.com>
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