From: | Julie Robinson <funkjunk(at)bellsouth(dot)net> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | SQL Query Newbie Help |
Date: | 2006-03-24 16:24:52 |
Message-ID: | 12287b48nref60f@corp.supernews.com |
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Thread: | |
Lists: | pgsql-sql |
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 | timestamp | 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 | timestamp | 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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