FailedChanges

Summary

  1. [SPARK-25736][SQL][TEST] add tests to verify the behavior of (details)
Commit e028fd3aed9e5e4c478f307f0a467b54b73ff0d5 by hyukjinkwon
[SPARK-25736][SQL][TEST] add tests to verify the behavior of
multi-column count
## What changes were proposed in this pull request?
AFAIK multi-column count is not widely supported by the mainstream
databases(postgres doesn't support), and the SQL standard doesn't define
it clearly, as near as I can tell.
Since Spark supports it, we should clearly document the current behavior
and add tests to verify it.
## How was this patch tested?
N/A
Closes #22728 from cloud-fan/doc.
Authored-by: Wenchen Fan <wenchen@databricks.com> Signed-off-by:
hyukjinkwon <gurwls223@apache.org>
The file was addedsql/core/src/test/resources/sql-tests/inputs/count.sql
The file was modifiedsql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Count.scala (diff)
The file was addedsql/core/src/test/resources/sql-tests/results/count.sql.out