On Wednesday 18 October 2006 14:15, Csaba Nagy wrote: > > The following query returns NULL in PG: > > SELECT NULL || 'fisk'; > > > > But in Oracle, it returns 'fisk': > > SELECT NULL || 'fisk' FROM DUAL; > > > > The latter seems more logical... > > Why would it be more logical ?
How many times do you *really* want to get the "not known" answer here instead of 'fisk'? To put it another way: When will it be *wrong* to return 'fisk'? > NULL means "value not known". I know. > Concatenate "value not known" with 'fisk' -> what's the logical answer? > > I would say the logical result is 'value not known'... if one of the > components is not known, how can you know what is the result ? That's like saying: SELECT sum(field) should return NULL(value not known) if some of the tuples are NULL, which is definitly not what you want. -- Andreas Joseph Krogh <[EMAIL PROTECTED]> Senior Software Developer / Manager gpg public_key: http://dev.officenet.no/~andreak/public_key.asc ------------------------+---------------------------------------------+ OfficeNet AS | The most difficult thing in the world is to | Karenslyst Allé 11 | know how to do a thing and to watch | PO. Box 529 Skøyen | somebody else doing it wrong, without | 0214 Oslo | comment. | NORWAY | | Mobile: +47 909 56 963 | | ------------------------+---------------------------------------------+ ---------------------------(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
