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https://issues.apache.org/jira/browse/CALCITE-6376?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17841034#comment-17841034
]
ShenDa commented on CALCITE-6376:
---------------------------------
Yep, I reproduced.
And I also found the root cause of this issus. This is because Calcite has a
class called ComparableList, which requires its elements to implement
Comparable. If the elements are not comparable, then a ClassCastException will
be thrown at runtime.
```java
/** List that is also comparable.
*
* <p>You can create an instance whose type
* parameter {@code T} does not extend {@link Comparable}, but you will get a
* {@link ClassCastException} at runtime when you call
* {@link #compareTo(Object)} if the elements of the list do not implement
* {@code Comparable}.
*
* @param <T> element type
*/
```
> Filtering CTE of at least 6 columns with QUALIFY operation results in
> exception
> -------------------------------------------------------------------------------
>
> Key: CALCITE-6376
> URL: https://issues.apache.org/jira/browse/CALCITE-6376
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.36.0
> Reporter: Austin Richardson
> Priority: Major
>
> Example query:
>
> {code:java}
> WITH MyCTE AS (
> SELECT
> column1,
> column2,
> column3,
> column4,
> column5,
> column6
> FROM (
> VALUES
> ('value1', 10, 5.0, 'data1', 'info1', 'test1'),
> ('value2', 20, 4.0, 'data2', 'info2', 'test2'),
> ('value3', 30, 3.0, 'data3', 'info3', 'test3'),
> ('value4', 40, 2.0, 'data4', 'info4', 'test4'),
> ('value5', 50, 1.0, 'data5', 'info5', 'test5')
> ) AS t(column1, column2, column3, column4, column5, column6)
> )
> SELECT *
> FROM MyCTE
> QUALIFY RANK() OVER (ORDER BY column3) = 1{code}
>
> And exception snippet:
>
> {code:java}
> Caused by: java.lang.ClassCastException: class
> org.apache.calcite.rex.RexInputRef cannot be cast to class
> java.lang.Comparable (org.apache.calcite.rex.RexInputRef is in unnamed module
> of loader org.springframework.boot.loader.LaunchedURLClassLoader @257f30f7;
> java.lang.Comparable is in module java.base of loader 'bootstrap')
> at
> org.apache.calcite.runtime.FlatLists$ComparableListImpl.get(FlatLists.java:1319)
> at
> org.apache.calcite.runtime.FlatLists$ComparableListImpl.get(FlatLists.java:1309)
> at
> java.base/java.util.AbstractList$Itr.next(AbstractList.java:373){code}
>
> Either removing one of the columns or the QUALIFY filter results in a
> successful query.
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