[SQL] Minor changes for DataFrame Implementation

[chenghao-intel]

No description provided.

[SparkQA]

Test build #26655 has started for PR 4339 at commit f63614b.

• This patch merges cleanly.

[SparkQA]

Test build #26655 has finished for PR 4339 at commit f63614b.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

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[marmbrus]

Can you put the real types here instead? (i.e. sortCols: String*) as the flow here is super confusing. Also I'd have most versions call sort(sortCol: String, sortCols: String*), where the actual work is done.

[rxin]

Hey @chenghao-intel thanks for doing this. I'm making changes to this file right now so I will roll your change in.

[chenghao-intel]

OK, I am closing it.