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https://issues.apache.org/jira/browse/CALCITE-2555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16620021#comment-16620021
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pengzhiwei edited comment on CALCITE-2555 at 9/19/18 4:45 AM:
--------------------------------------------------------------
[~vladimirsitnikov] There is a problem when using Strong.isNull for
RexSimplify.The case "null not in null non-correlated" generated a wrong result.
{code:java}
# Test project null NOT IN null non-correlated
select sal,
cast(null as int) NOT IN (
select cast(null as int)
from "scott".dept)
from "scott".emp;
SAL | EXPR$1
---------+--------
1100.00 | true
1250.00 | true
1250.00 | true
1300.00 | true
1500.00 | true
1600.00 | true
2450.00 | true
2850.00 | true
2975.00 | true
3000.00 | true
3000.00 | true
5000.00 | true
800.00 | true
950.00 | true
(14 rows)
{code}
The correct result should be "null" but not "true".
So I think there is a risk to do this.
was (Author: pzw2018):
[~vladimirsitnikov] There is a problem when using Strong.isNull for
RexSimplify.The case "null not in null non-correlated" generated wrong result.
{code:java}
# Test project null NOT IN null non-correlated
select sal,
cast(null as int) NOT IN (
select cast(null as int)
from "scott".dept)
from "scott".emp;
SAL | EXPR$1
---------+--------
1100.00 | true
1250.00 | true
1250.00 | true
1300.00 | true
1500.00 | true
1600.00 | true
2450.00 | true
2850.00 | true
2975.00 | true
3000.00 | true
3000.00 | true
5000.00 | true
800.00 | true
950.00 | true
(14 rows)
{code}
The correct result should be "null" but not "true".
So I think there is a risk to do this.
> RexSimplify: >=(true, null) could be simplified to null
> -------------------------------------------------------
>
> Key: CALCITE-2555
> URL: https://issues.apache.org/jira/browse/CALCITE-2555
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.17.0
> Reporter: Vladimir Sitnikov
> Assignee: Julian Hyde
> Priority: Major
> Labels: newbie
>
> {code:java}
> @Test public void simplifyComparisonWithNull() {
> checkSimplify2(ge(trueLiteral, falseLiteral), "true", "true");
> checkSimplify2(ge(trueLiteral, nullBool), "null", "false");
> checkSimplify2(ge(nullBool, nullBool), "null", "false");
> }
> {code}
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