You're making the assumption that he's using 4.1.x. He didn't state which version he's using so your solution may be of no use to him.
-- T --- Matt Warden <[EMAIL PROTECTED]> wrote: > On Fri, 06 Aug 2004 13:17:42 -0400, Michael Stassen > <[EMAIL PROTECTED]> wrote: > > You need a LEFT JOIN: > > > > SELECT ticket_number > > FROM purchased_items LEFT JOIN purchases > > ON purchased_items.ticket_number = > purchases.ticket_number > > WHERE purchases.ticket_number IS NULL; > > > No, actually he doesn't. > > SELECT ticket_number > FROM purchased_items > WHERE ticket_number NOT IN > (SELECT ticket_number FROM purchases); > > The above will most certainly be faster than any > join, because it is > only a couple projections and a simple selection > over ticket_number > (which is almost certainly indexed). > > Although, I suppose if this is only a maintenance > query (I suspect it > is), then it probably doesn't matter. But, the > bottom line is: if you > can avoid join, do it. There's only so much the > query optimizer can > do. > > > > > -- > > Matt Warden > Berry Neuroscience Lab > Department of Psychology > Miami University > > > > This email proudly and graciously contributes to > entropy. > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > __________________________________ Do you Yahoo!? Yahoo! Mail - 50x more storage than other providers! http://promotions.yahoo.com/new_mail -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
