Unexpected Null behavior for ScalarValue::partial_cmp() #19579
Description
Describe the bug
For partial_cmp() function for ScalarValue
The current behavior is unexpected:
// this test can be added to the above file that `partial_cmp()` lives
#[test]
fn scalar_partial_ordering_nulls() {
use ScalarValue::*;
assert_eq!(
Int32(Some(3)).partial_cmp(&Int32(None)),
Some(Ordering::Greater)
);
assert_eq!(
Int32(None).partial_cmp(&Int32(Some(3))),
Some(Ordering::Less)
);
} The comparison between ScalarValue { type: Int32, val: 3 } and ScalarValue { type: Int32, val: Null } returns Some(_), whereas I expected None, indicating that the values are not comparable, consistent with SQL’s three-valued logic.
Additionally, comparing Null with Null returns Some(Ordering::Equal) instead of None.
We should either:
- Fix this behavior to follow SQL’s null comparison semantics, or
- If this non-standard null behavior is intentional for specific reasons, explicitly document it in the comments.
To Reproduce
No response
Expected behavior
No response
Additional context
No response