Re: [PERFORM] OT - select + must have from - sql standard syntax?
The spec does require a FROM clause in SELECT (at least as of SQL99, did not check SQL2003). However, it's clearly mighty useful to allow FROM to be omitted for simple compute-this-scalar-result problems. You should respond to the Oracle guy that SELECT whatever FROM dual is not in the standard either (certainly the spec does not mention any such table). Thanks for your answers guys. I was pretty sure DUAL wasn't in the standard (never seen it outside an oracle context) but wasn't at all sure about the FROM. Cheers Antoine ps. shame the standard isn't freely consultable to save you guys silly OT questions! -- This is where I should put some witty comment. ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
Re: [PERFORM] OT - select + must have from - sql standard syntax?
-Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Greg Stark Sent: Tuesday, June 13, 2006 11:16 PM Subject: Re: [PERFORM] OT - select + must have from - sql standard syntax? [SNIP] Well you could always create a dual, it was always just a regular table. We used to joke about what would happen to Oracle if you inserted an extra row in it... I've never used Oracle, so I don't understand why its called dual when it only has one row? Shouldn't it be called single? :\ Dave ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[PERFORM] OT - select + must have from - sql standard syntax?
Hi, I don't have a copy of the standard on hand and a collegue is claiming that there must be a from clause in a select query (he is an oracle guy). This doesn't seem to be the case for postgres... does anyone know? Cheers Antoine ps. any one of them will do... -- This is where I should put some witty comment. ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [PERFORM] OT - select + must have from - sql standard syntax?
On Tue, Jun 13, 2006 at 02:43:45PM +0200, Antoine wrote: Hi, I don't have a copy of the standard on hand and a collegue is claiming that there must be a from clause in a select query (he is an oracle guy). This doesn't seem to be the case for postgres... does anyone know? Dunno, but I know that other databases (at least DB2) don't require FROM either. In Oracle, if you want to do something like SELECT now(); you actually have to do SELECT now() FROM dual; where dual is a special, hard-coded table in Oracle that has only one row. Personally, I find their approach to be pretty stupid. -- Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED] Pervasive Software http://pervasive.comwork: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [PERFORM] OT - select + must have from - sql standard syntax?
Jim C. Nasby [EMAIL PROTECTED] writes: On Tue, Jun 13, 2006 at 02:43:45PM +0200, Antoine wrote: I don't have a copy of the standard on hand and a collegue is claiming that there must be a from clause in a select query (he is an oracle guy). This doesn't seem to be the case for postgres... does anyone know? Dunno, but I know that other databases (at least DB2) don't require FROM either. The spec does require a FROM clause in SELECT (at least as of SQL99, did not check SQL2003). However, it's clearly mighty useful to allow FROM to be omitted for simple compute-this-scalar-result problems. You should respond to the Oracle guy that SELECT whatever FROM dual is not in the standard either (certainly the spec does not mention any such table). And in any case an Oracle fanboy has got *no* leg to stand on when griping about proprietary extensions to the spec. regards, tom lane ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [PERFORM] OT - select + must have from - sql standard syntax?
Tom Lane [EMAIL PROTECTED] writes: The spec does require a FROM clause in SELECT (at least as of SQL99, did not check SQL2003). However, it's clearly mighty useful to allow FROM to be omitted for simple compute-this-scalar-result problems. You should respond to the Oracle guy that SELECT whatever FROM dual is not in the standard either (certainly the spec does not mention any such table). Well you could always create a dual, it was always just a regular table. We used to joke about what would happen to Oracle if you inserted an extra row in it... Oracle used to always require FROM, if it has stopped requiring it then that's new. I had heard it had special-cased dual in later versions to avoid the table access overhead, I suspect these two changes are related. -- greg ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
