Title: Message
Mathias,
>Im sorry to disappoint you but this
is an anti-performance solution.
>Use joins rathers than subqueries,
and don't use joins if you can (all data in the mother table).
This 2-query solution uses neither a join
nor a subquery. What do you mean?
PB
-----
mathias fatene wrote:
Hi,
Im sorry to disappoint you but this is
an anti-performance solution.
Use joins rathers than subqueries, and
don't use joins if you can (all data in the mother table).
Imagine that table2 has 30.000.000 records,
and not good indexes. you can wait for your answer a long time.
Best
Regards
--------------------
Mathias
FATENE
Hope
that helps
*This
not an official mysql support answer
Jeff,
Then do it with 2 queries,
SELECT @d := MAX( datestamp )
FROM table2
WHERE parentID = X;
SELECT *
FROM table2
WHERE parentID = X AND [EMAIL PROTECTED];
PB
-----
Jeff McKeon wrote:
Thanks all but I don't have a mysql version high enough for subqueries.
Thanks,
Jeff
-----Original Message-----
From: Peter Brawley [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 25, 2005 4:01 PM
To: Jeff McKeon
Cc: mysql@lists.mysql.com
Subject: Re: Query question
Jeff,
Something like ...
SELECT *
FROM table2 AS a
WHERE datestamp = (
SELECT MAX( b.datestamp )
FROM table2 AS b
WHERE a.parentID = b.parentID
);
PB
-----
Jeff McKeon wrote:
I have a table that contains records that link back to a
main talbe in
a many to one configuration linked by table1.id = table2.parentid
Table1 (one)
Table2 (many)
I want to pull the latest records from table2 for each
record in table1
where certain criteria applie.
So, if record 100 in table1 links to 5 corresponding records
in table2,
I want to pull the latest record from table2 where table2.parentid =
100 and table2.user not like 'john'
There is a datestamp field in table2.
I just can't figure out how to do this.
Thanks,
Jeff
--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 4/21/2005
No virus found in this incoming message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 4/21/2005
|
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 4/21/2005
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
