The current "count" hash aggregate kernel counts either all non-null or all null values, but doesn't count all values regardless of nullity (i.e. SQL "count(\*)" or Pandas size()).

Reporter: David Li / @lidavidm
Assignee: David Li / @lidavidm

Related issues:

• [C++] Implement hash_aggregate kernels (umbrella issue) (is a child of)

PRs and other links:

• GitHub Pull Request #10895

_{Note: This issue was originally created as ARROW-13574. Please see the migration documentation for further details.}