> Behalf Of Keith Medcalf > Sent: Saturday, October 13, 2018 6:53 PM ... > > > Lastly, I'm assuming that 'IS' and 'IS NOT' is functionally > > equivalent to the '=' and '<>' operators? > > Or is there some subtle difference > > As long as neither the LHS or the RHS are null, then IS and > IS NOT are the same as == and <> respectively. > > However, if you use the "comparison" operators (==, <>) then > if either the LHS or the RHS or both are NULL, then the > results is NULL (that is, false). For the purpose of these > comparisons NULL is a value that is neither equal to nor not > equal to any other value, including null. > > IS and IS NOT mean that NULL is a distinct value and NULL IS > NULL is TRUE, NULL IS NOT 7 is TRUE, and so on and so forth. >
Thanks for the confirmation of the behaviour of 'is' in sqlite. And if anyone has comnments regarding the first two issues I mentioned, namely the absence of support of NOT MATCH, NOT LIKE, NOT GLOB, NOT REGEXP in xBestIndex() And also the meaning/use of SQLITE_INDEX_CONSTRAINT_FUNCTION, that would be super helpful. Cheers! -dave _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
