Interesting comment. I find by experiment that (select * from FOO order by a desc limit 10) order by a; removes duplicates, but, if I drop the second order clause, (select * from FOO order by a desc limit 10); duplicates are retained.
Why is the first a union, but not the second? Just curious. > From: "Keith C. Ivey" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Date: Fri, 23 Apr 2004 11:27:38 -0400 > Subject: Re: first LIMIT then ORDER > On 23 Apr 2004 at 7:23, Bill Easton wrote: > > The last suggestion is useful when you do care which entries you get, > > as you can use one order for limit and another for presentation. For > > example, if you'd like the LAST 10 rows, but sorted in FORWARD order, > > you can use something like > > > > (select * from HISTORY order by version desc limit 10) order by > > version; > > > > And I thought I'd have to wait for subqueries... > One small gotcha that Anders Karlsson pointed out to me through Paul > DuBois: This one-query union syntax doesn't allow you to use the ALL > keyword after UNION (since the UNION keyword isn't even there). That > means it will always eliminate duplicate rows (like DISTINCT). That > hasn't come up when I've used it, since I've never been selecting > result sets that could contain duplicate rows, but it's something to > keep in mind. > -- > Keith C. Ivey <[EMAIL PROTECTED]> > Tobacco Documents Online > http://tobaccodocuments.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
