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https://issues.apache.org/jira/browse/CALCITE-3464?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16963892#comment-16963892
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Wang Yanlin commented on CALCITE-3464:
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Hi， [~zabetak] and [~kgyrtkirk], very thanks for your fast reply.
At first I thought filter condition like *name <> NULL* will just filter out
rows that have null value for name column.
But I checked filter by null on mysql. It's really returns an empty result.
So, that's no problem here. I'll just close this jira.
!pics.jpg!
> RexSimplify simplifies plan having filter with NULL to empty values
> -------------------------------------------------------------------
>
> Key: CALCITE-3464
> URL: https://issues.apache.org/jira/browse/CALCITE-3464
> Project: Calcite
> Issue Type: Bug
> Reporter: Wang Yanlin
> Priority: Major
> Attachments: pics.jpg
>
>
> When filter by comparing to null in sql, the plan will get empty result
> {code:java}
> @Test public void testSimplifyItemEqualNull() {
> String query = "select * from sales.customer as t1 where name = NULL";
> sql(query)
> .withTester(t -> createDynamicTester())
> .withRule(ReduceExpressionsRule.FILTER_INSTANCE)
> .check();
> }
> {code}
> The plan after optimization is like this
> {code:java}
> LogicalProject(**=[$1])
> LogicalValues(tuples=[[]])
> {code}
> The optimized plan will get empty result, is this the result we want?
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