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
PRIMARYKEY (id)
);