> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Chris Green > Sent: Thursday, December 02, 2004 9:56 AM > To: [EMAIL PROTECTED] > Subject: [GENERAL] UNION with ORDER BY -allowed? > > > It's not quite clear (to me at least) whether I can have a UNION and > an ORDER BY in a SELECT statement. > > What I want to do is:- > > SELECT > col1, col2, col5, col6 > FROM > table > WHERE > col2 = 'X' > UNION > SELECT > col3, col4, col5, col6 > FROM > table > WHERE > col4 = 'X' > ORDER BY > coalesce(col1, col3) > > Is this valid syntax allowed by postgresql? (I'm not at the system > where postgresql is installed at the moment so I can't just try it) Yes, provided the columns are the same data types (or you can cast them to make them the same)
> > col1 and col3 are both DATE columns. col2 and col4 are both > varchar(1). > > I want the ORDER BY to order the result of the UNION. It does, per SQL spec. Nothing less would make sense if you ask me. :) Terry Fielder Manager Software Development and Deployment Great Gulf Homes / Ashton Woods Homes [EMAIL PROTECTED] Fax: (416) 441-9085 > > -- > Chris Green ([EMAIL PROTECTED]) > > "Never ascribe to malice, that which can be explained by > incompetence." > > ---------------------------(end of > broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
