[SPARK-45904][SQL][CONNECT] Mode function should supports sort with order direction

[beliefer]

What changes were proposed in this pull request?

Currently, the mode aggregate function only support sort desc with the input column.
But the mainstream database (e.g. H2 and Postgres) supports sort desc or asc.

#43663 will support MODE() WITHIN GROUP (ORDER BY col [ASC|DESC]) syntax.

Why are the changes needed?

Mode function should supports sort with order direction.

Does this PR introduce any user-facing change?

'No'.
New feature.

How was this patch tested?

Test cases updated.

Was this patch authored or co-authored using generative AI tooling?

'No'.

[beliefer]

I think it's not worth let isSortAsc as the child expression of Mode due to it's always none or foldable.

[peter-toth]

Actually this is literally the same implementation I came up with internally before I added deterministic mode in #42755. But then we reduced the sort argument (isSortAsc in this PR) to a simple deterministic flag to keep the change simple.

@beliefer, are you referring to the isSortAsc argument of the mode function or are you referring to the new MODE() WITHIN GROUP (ORDER BY col [ASC|DESC]) syntax by "mainstream databases support"?

cc @cloud-fan, @srielau

[beliefer]

@beliefer, are you referring to the isSortAsc argument of the mode function or are you referring to the new MODE() WITHIN GROUP (ORDER BY col [ASC|DESC]) syntax by "mainstream databases support"?

Because I want add the new MODE() WITHIN GROUP (ORDER BY col [ASC|DESC]) syntax supported by mainstream databases. Please see #43663.

I found that the current implementation of mode only supports sort by column ASC if we make deterministicExpr is true.
We should let mode also supports by column DESC

[beliefer]

ping @MaxGekk cc @cloud-fan

[beliefer]

The GA failure is unrelated.

[cloud-fan]

If we do want to support specify ordering, we should support ordering columns. I don't agree with this partial API change. Let's finish the SQL side first, then we can think about how the Scala API should look like.

[beliefer]

I will close due to #44184 merged.