[ https://issues.apache.org/jira/browse/CALCITE-2393?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16530271#comment-16530271 ]
Julian Hyde commented on CALCITE-2393: -------------------------------------- I agree with [~kgyrtkirk]. The thing to realize about {{unknownAsFalse}} -- something I got wrong for quite a while -- is that it only applies to the final result; the internal calculations (such as "null <> 5") still occur using 3-valued logic. It was a mistake to make {{unknownAsFalse}} a field in {{RexSimplify}}. It should be a method argument, so that when you pass through NOT (say) it can flip sign. See CALCITE-2326. > RexSimplify optimization error for expression 'x is not null and x <> 5' > ------------------------------------------------------------------------- > > Key: CALCITE-2393 > URL: https://issues.apache.org/jira/browse/CALCITE-2393 > Project: Calcite > Issue Type: Bug > Components: core > Affects Versions: 1.16.0 > Reporter: pengzhiwei > Assignee: Julian Hyde > Priority: Major > Fix For: 1.17.0 > > > After the optimization of RexSimplify,the expression 'x is not null and x > <> 5' (x is nullable) is optimized to 'x<> 5' (RexSimplify#unknownAsFalse is > true). I think it is not a correct result because when x is null, null<> 5 > should return true,while 'x is not null and x <> 5' return false. > I think the optimization for "is not null" in > RexSimplify#simplifyAnd2ForUnknownAsFalse should exclude the case of > not-equal operator. > I really confused with this optimization, can you give some > suggestion,thanks! > > > -- This message was sent by Atlassian JIRA (v7.6.3#76005)