On Wed, Oct 18, 2006 at 02:28:50PM +0200, Andreas Joseph Krogh wrote: > 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...
> 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'? In general, if you pass a NULL to a function, you get a NULL return. An operator is just a function call. IIRC, this works on oracle too: SELECT NULL = ''; returns true. On postgresql it return null (sql standard). By following your suggestion we would get the following oddity: SELECT NULL = '', NULL || 'fisk' = '' || 'fisk'; We would return NULL for the first and true for the second. Surely that's not logical? Have a nice day, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to > litigate.
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