On 3/6/21 8:55 PM, David Fetter wrote: > On Wed, Mar 03, 2021 at 03:30:15PM +0100, Peter Eisentraut wrote: >> On 10.02.21 06:42, Kyotaro Horiguchi wrote: >>> We already had CREATE AGGREATE at the time, so BIT_XOR can be >>> thought as it falls into the same category with BIT_AND and >>> BIT_OR, that is, we may have BIT_XOR as an intrinsic aggregation? >> >> I think the use of BIT_XOR is quite separate from BIT_AND and >> BIT_OR. The latter give you an "all" or "any" result of the bits >> set. BIT_XOR will return 1 or true if an odd number of inputs are 1 >> or true, which isn't useful by itself. But it can be used as a >> checksum, so it seems pretty reasonable to me to add it. Perhaps >> the use case could be pointed out in the documentation. > > If this is the only use case, is there some way to refuse to execute > it if it doesn't contain an unambiguous ORDER BY, as illustrated > below? > > SELECT BIT_XOR(b ORDER BY a, c)... /* works */ > SELECT BIT_XOR(b) OVER (ORDER BY a, c)... /* works */ > SELECT BIT_XOR(b) FROM... /* errors out */
Why would such an error be necessary, or even desirable? -- Vik Fearing
