unload_table Macro extended to accept WHERE clause in SELECT statement

Describe the feature

An update to the unload_table macro that would allow a user to pass in a WHERE clause to filter specific rows within table to unload into S3. This is possible via using the Redshift UNLOAD command but limited with the macro to an entire SELECT of the table.

Describe alternatives you've considered

Alternatives is to just pass the raw SQL into a post_hook to extract the specific rows wanted rather than using the unload_table macro

Additional context

Redshift specific

Who will this benefit?

Users who want to unload a subset of the table rather than the entire table as this might not suit all use cases.

[gboro54]

Could you not materialize a view with the correct filtering and then run the unload macro? I do agree the where clause would be useful but this would probably be a workaround and allow you to still leverage the macro