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Zoltan Haindrich commented on CALCITE-2393: ------------------------------------------- I think that "null<> 5 should return true" is not correct; it seems logical, but by agreement unknown is not following "that" convention - and becomes unknown; see here for more informations: https://modern-sql.com/concept/three-valued-logic > 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)