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https://issues.apache.org/jira/browse/IOTDB-4407?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17605023#comment-17605023
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李伟豪 commented on IOTDB-4407:
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!image-2022-09-15-09-07-27-719.png!
Test SQLs are in 'IoTDBHavingIT'
> Where is null clause will not return the rows with all null which satisfied
> the where clause
> --------------------------------------------------------------------------------------------
>
> Key: IOTDB-4407
> URL: https://issues.apache.org/jira/browse/IOTDB-4407
> Project: Apache IoTDB
> Issue Type: Bug
> Affects Versions: 0.14.0-SNAPSHOT
> Environment: Windows 10
> Reporter: Tao Yi
> Assignee: liaolanyu
> Priority: Minor
> Attachments: image-2022-09-14-16-29-22-030.png,
> image-2022-09-14-16-29-32-716.png, image-2022-09-14-16-29-47-709.png,
> image-2022-09-15-09-07-27-719.png
>
>
> In 0.14.0 version, it seems that the where clause will return all rows
> satisfied the where condition, even though the returned result are all null.
> This is the comparison of the same clause in 0.14.0-SNAPSHOT and 0.13.1.
> !image-2022-09-14-16-29-22-030.png|width=997,height=612!
> !image-2022-09-14-16-29-32-716.png|width=995,height=695!
> However, when I try IS NULL and IS NOT NULL clause, they act different: IS
> NOT NULL clause will return all the rows satisfied, but IS NULL clause will
> not.
> I execute the following query in IoTDB-client:
> create timeseries root.sg1.d1.num with datatype=INT32, encoding=plain;
> create timeseries root.sg1.d1.tem with datatype=INT32, encoding=plain;
> create timeseries root.sg1.d1.tem2 with datatype=INT32, encoding=plain;
> insert into root.sg1.d1(timestamp, num, tem, tem2) values(0, 2, 37, 1);
> insert into root.sg1.d1(timestamp, num, tem, tem2) values(1, null, null, 1);
> insert into root.sg1.d1(timestamp, num, tem, tem2) values(2, 1, null, 1);
> insert into root.sg1.d1(timestamp, num, tem, tem2) values(3, null, 1, 1);
> select * from root.sg1.d1;
> select num from root.sg1.d1 where tem is not null;
> select num from root.sg1.d1 where tem is null;
> The result is in the following screenshot:
> !image-2022-09-14-16-29-47-709.png|width=991,height=678!
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