rubenada commented on a change in pull request #1322: [CALCITE-3198]
ReduceExpressionsRule.FILTER_INSTANCE does not reduce 'NOT(x=a AND x=b)'
URL: https://github.com/apache/calcite/pull/1322#discussion_r305710205
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File path: core/src/main/java/org/apache/calcite/rex/RexSimplify.java
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@@ -1624,6 +1626,24 @@ private RexNode simplifyOrs(List<RexNode> terms,
RexUnknownAs unknownAs) {
continue;
}
}
+ break;
+ case NOT_EQUALS:
+ Comparison notEqualsComparison =
+ Comparison.of(term, node -> RexUtil.isReferenceOrAccess(node,
false));
+ if (notEqualsComparison != null) {
+ Comparison prevNotEqualsComparison =
notEqualsComparisonMap.get(notEqualsComparison.ref);
+ if (prevNotEqualsComparison == null) {
+ notEqualsComparisonMap.put(notEqualsComparison.ref,
notEqualsComparison);
+ } else {
+ Comparable comparable1 = notEqualsComparison.literal.getValue();
+ Comparable comparable2 =
prevNotEqualsComparison.literal.getValue();
+ //noinspection unchecked
+ if (comparable1.compareTo(comparable2) != 0) {
+ return rexBuilder.makeLiteral(true);
Review comment:
Thanks for your feedback, @kgyrtkirk .
If I understand correctly, you say that the simplification
`x != 0 || x!= 1 => TRUE`
Can only be done in unknownas.TRUE mode or if x's type is not nullable.
Otherwise, it should be simplified as:
`x != 0 || x!= 1 => x IS NOT NULL`
Regarding the expression:
`x = 0 && x = 1 => FALSE`
I have verified, and right now it seems that this is only simplified with
unknownas.FALSE. I assume this behavior is correct, right?
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