I know this is a common problem, and I've been struggling with it for a full
day now but I can't get it.
I also tried a few sites for examples:
http://www.artfulsoftware.com/infotree/queries.php#101
http://forums.devarticles.com/general-sql-development-47/select-max-datetime
-problem-10210.html
Anyways, pretty standard situation:
CREATE TABLE `customers` (
`customer_id` int(10) unsigned NOT NULL auto_increment,
`email` varchar(64) NOT NULL default '',
`name` varchar(128) NOT NULL default '',
`username` varchar(32) NOT NULL,
...
);
CREATE TABLE `customers_subscriptions` (
`subscription_id` bigint(12) unsigned NOT NULL default '0',
`customer_id` int(10) unsigned NOT NULL default '0',
`date` date NOT NULL default '0000-00-00',
...
);
I want to show a table where I list out the ID, email, username, and LAST
SUBSCRIPTION.
I need this data in TWO ways:
The FIRST way, is with a query JOINing the two tables so that I can easily
display that HTML table mentioned. That is ALL customers and the latest
subscription they have.
The SECOND way is when I drill into the customer, I already know the
customer_id and so don't need to JOIN with that table, I just want to get
the proper row from the customers_subscriptions table itself.
SELECT * FROM `customers_subscriptions` WHERE customer_id = 7 ORDER BY
`date` DESC;
subscription_id processor customer_id date
--------------- --------- ----------- ----------
134126370 chargem 7 2005-08-04
1035167192 billme 7 2004-02-08
SELECT MAX(`date`) FROM `customers_subscriptions` WHERE customer_id = 7
GROUP BY customer_id;
gives me 2005-08-04 obviously, but as you all know, mySQL completely takes a
crap on your face when you try what would seem to be the right query:
SELECT subscription_id, MAX(`date`) FROM `customers_subscriptions` WHERE
customer_id = 7 GROUP BY customer_id;
subscription_id MAX(`date`)
--------------- -----------
1035167192 2005-08-04
Notice how I have the correct DATE, but the wrong subscription_id.
In the example web sites above, they seem to deal more with finding the
MAX(subscription_id), which in my case will not work.
I need the max DATE and the corresponding row (with matching
subscription_id).
Thanks,
d
