From db11ee5e56e5fac59895c772a9a87c5ac86888ef Mon Sep 17 00:00:00 2001
From: tedyu <yuzhihong@gmail.com>
Date: Mon, 2 Nov 2015 13:51:53 -0800
Subject: [PATCH] [SPARK-11371] Make "mean" an alias for "avg" operator
From Reynold in the thread 'Exception when using some aggregate operators' (http://search-hadoop.com/m/q3RTt0xFr22nXB4/):
I don't think these are bugs. The SQL standard for average is "avg", not "mean". Similarly, a distinct count is supposed to be written as "count(distinct col)", not "countDistinct(col)".
We can, however, make "mean" an alias for "avg" to improve compatibility between DataFrame and SQL.
Author: tedyu <yuzhihong@gmail.com>
Closes #9332 from ted-yu/master.
---
.../spark/sql/catalyst/analysis/FunctionRegistry.scala | 1 +
.../spark/sql/hive/execution/AggregationQuerySuite.scala | 9 +++++++++
2 files changed, 10 insertions(+)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
index 5f3ec74ac0..24c1a7b7ac 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala
@@ -185,6 +185,7 @@ object FunctionRegistry {
expression[Last]("last"),
expression[Last]("last_value"),
expression[Max]("max"),
+ expression[Average]("mean"),
expression[Min]("min"),
expression[Stddev]("stddev"),
expression[StddevPop]("stddev_pop"),
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/AggregationQuerySuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/AggregationQuerySuite.scala
index 0cf0e0aab9..74061db0f2 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/AggregationQuerySuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/AggregationQuerySuite.scala
@@ -298,6 +298,15 @@ abstract class AggregationQuerySuite extends QueryTest with SQLTestUtils with Te
""".stripMargin),
Row(1, 20.0) :: Row(2, -0.5) :: Row(3, null) :: Row(null, 10.0) :: Nil)
+ checkAnswer(
+ sqlContext.sql(
+ """
+ |SELECT key, mean(value)
+ |FROM agg1
+ |GROUP BY key
+ """.stripMargin),
+ Row(1, 20.0) :: Row(2, -0.5) :: Row(3, null) :: Row(null, 10.0) :: Nil)
+
checkAnswer(
sqlContext.sql(
"""
--
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