>-----Original Message----- >From: baron.schwa...@gmail.com [mailto:baron.schwa...@gmail.com] On >Behalf Of Baron Schwartz >Sent: Wednesday, January 07, 2009 9:54 AM >To: Jerry Schwartz >Cc: mysql@lists.mysql.com >Subject: Re: Limit within groups > >On Tue, Jan 6, 2009 at 3:13 PM, Jerry Schwartz ><jschwa...@the-infoshop.com> wrote: >> Each account has multiple customers, and each customer has multiple >sales. I >> want to get the top 20 customers for each account. > >http://www.xaprb.com/blog/2006/12/07/how-to-select-the-firstleastmax- >row-per-group-in-sql/ > >Keep reading, it talks about top N per group later on in the post. >"Select the top N rows from each group" > [JS] Thanks for the pointer. Unless I'm misunderstanding them, none of the techniques look very promising. I need the top 20 customers for each of 15 or more accounts, but each customer has many records so I need to rank them by sum() for each customer and then select the first 20 for each account.
It looks as though I'd have build a separate query for each account, and then UNION them all together. I'm trying to avoid that, especially since some of the account Ids are actually Japanese words. What I really need is some kind of "for each" functionality. My goal is tantalizingly just out of reach. >-- >Baron Schwartz, Director of Consulting, Percona Inc. >Our Blog: http://www.mysqlperformanceblog.com/ >Our Services: http://www.percona.com/services.html -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
