Aggregate FILTER fails on NULL predicate

[pchintar]

Describe the bug

Aggregate and window aggregate FILTER clauses currently fail with an internal error for FILTER (WHERE NULL).

To Reproduce

Aggregate:

SELECT count(*) FILTER (WHERE NULL);

Output:

Internal error: Cannot create filter_array from non-boolean predicates.

Window aggregate:

SELECT count(*) FILTER (WHERE NULL) OVER ()
FROM (VALUES (1)) AS t(x);

Output:

Internal error: could not cast array of type Null to BooleanArray.

Expected behavior

The equivalent queries with a boolean-typed NULL predicate already work:

SELECT count(*) FILTER (WHERE CAST(NULL AS BOOLEAN));

0

SELECT sum(1) FILTER (WHERE CAST(NULL AS BOOLEAN));

NULL

Untyped NULL predicates in FILTER clauses should behave consistently rather than producing an internal error.

Environment

• DataFusion 53.1.0
• Reproduced in datafusion-cli

[mkleen]

take

[pchintar]

take

hi @mkleen thnx for showing interest on my issue, so I already worked on the fix for this issue and opened the PR for it just now.