apache / apache/iotdb

[Bug] SQL aggregate functions return null value exceptions under specific predicate expressions.

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#14,216 2 comments 0 reactions 1 assignee Claimed by @JackieTien97 View on GitHub
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Description

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/iotdb/issues) and found nothing similar.

### Version

version 1.3.3 (Build: ad95a7e)

### Describe the bug and provide the minimal reproduce step

```
DROP DATABASE root.db0
CREATE DATABASE root.db0

CREATE TIMESERIES root.db0.t1 WITH datatype=INT32;
INSERT INTO root.db0(timestamp, t1) VALUES (1641024000000, 1);

# query 1
SELECT COUNT(t1) AS ref0 FROM root.db0 WHERE t1 < -1 GROUP BY ([1641024000000, 1641024002000),1s,1s);

# query 2
SELECT COUNT(t1) AS ref0 FROM root.db0 WHERE FALSE GROUP BY ([1641024000000, 1641024002000),1s,1s);
```

### What did you expect to see?

Query 1 returned result set: 0 and 0

Query 2 returned result set: 0 and 0

### What did you see instead?

Query 1 returned result set: 0 and 0

Query 2 returned result set: **Empty set.**

### Anything else?

Dear IoTDB team, After filtering through predicate expressions, both Query 1 and Query 2 are expected to result in empty result sets. However, Query 1 can return a null value when there are no input rows or all values are null, while Query 2 returns an **Empty set**, which does not align with the expectation. This issue also exists with other aggregate function expressions. It may cause confusion for users in downsampling query scenarios.

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

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