From 6f6bb0e893c8370cbab4d63a56d74e00cb7f3cf6 Mon Sep 17 00:00:00 2001
From: Yanbo Liang <ybliang8@gmail.com>
Date: Thu, 26 Nov 2015 19:00:36 -0800
Subject: [PATCH] [SPARK-12011][SQL] Stddev/Variance etc should support
columnName as arguments
Spark SQL aggregate function:
```Java
stddev
stddev_pop
stddev_samp
variance
var_pop
var_samp
skewness
kurtosis
collect_list
collect_set
```
should support ```columnName``` as arguments like other aggregate function(max/min/count/sum).
Author: Yanbo Liang <ybliang8@gmail.com>
Closes #9994 from yanboliang/SPARK-12011.
---
.../org/apache/spark/sql/functions.scala | 86 +++++++++++++++++++
.../spark/sql/DataFrameAggregateSuite.scala | 3 +
2 files changed, 89 insertions(+)
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
index 276c5dfc8b..e79defbbbd 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
@@ -214,6 +214,16 @@ object functions extends LegacyFunctions {
*/
def collect_list(e: Column): Column = callUDF("collect_list", e)
+ /**
+ * Aggregate function: returns a list of objects with duplicates.
+ *
+ * For now this is an alias for the collect_list Hive UDAF.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def collect_list(columnName: String): Column = collect_list(Column(columnName))
+
/**
* Aggregate function: returns a set of objects with duplicate elements eliminated.
*
@@ -224,6 +234,16 @@ object functions extends LegacyFunctions {
*/
def collect_set(e: Column): Column = callUDF("collect_set", e)
+ /**
+ * Aggregate function: returns a set of objects with duplicate elements eliminated.
+ *
+ * For now this is an alias for the collect_set Hive UDAF.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def collect_set(columnName: String): Column = collect_set(Column(columnName))
+
/**
* Aggregate function: returns the Pearson Correlation Coefficient for two columns.
*
@@ -312,6 +332,14 @@ object functions extends LegacyFunctions {
*/
def kurtosis(e: Column): Column = withAggregateFunction { Kurtosis(e.expr) }
+ /**
+ * Aggregate function: returns the kurtosis of the values in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def kurtosis(columnName: String): Column = kurtosis(Column(columnName))
+
/**
* Aggregate function: returns the last value in a group.
*
@@ -386,6 +414,14 @@ object functions extends LegacyFunctions {
*/
def skewness(e: Column): Column = withAggregateFunction { Skewness(e.expr) }
+ /**
+ * Aggregate function: returns the skewness of the values in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def skewness(columnName: String): Column = skewness(Column(columnName))
+
/**
* Aggregate function: alias for [[stddev_samp]].
*
@@ -394,6 +430,14 @@ object functions extends LegacyFunctions {
*/
def stddev(e: Column): Column = withAggregateFunction { StddevSamp(e.expr) }
+ /**
+ * Aggregate function: alias for [[stddev_samp]].
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def stddev(columnName: String): Column = stddev(Column(columnName))
+
/**
* Aggregate function: returns the sample standard deviation of
* the expression in a group.
@@ -403,6 +447,15 @@ object functions extends LegacyFunctions {
*/
def stddev_samp(e: Column): Column = withAggregateFunction { StddevSamp(e.expr) }
+ /**
+ * Aggregate function: returns the sample standard deviation of
+ * the expression in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def stddev_samp(columnName: String): Column = stddev_samp(Column(columnName))
+
/**
* Aggregate function: returns the population standard deviation of
* the expression in a group.
@@ -412,6 +465,15 @@ object functions extends LegacyFunctions {
*/
def stddev_pop(e: Column): Column = withAggregateFunction { StddevPop(e.expr) }
+ /**
+ * Aggregate function: returns the population standard deviation of
+ * the expression in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def stddev_pop(columnName: String): Column = stddev_pop(Column(columnName))
+
/**
* Aggregate function: returns the sum of all values in the expression.
*
@@ -452,6 +514,14 @@ object functions extends LegacyFunctions {
*/
def variance(e: Column): Column = withAggregateFunction { VarianceSamp(e.expr) }
+ /**
+ * Aggregate function: alias for [[var_samp]].
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def variance(columnName: String): Column = variance(Column(columnName))
+
/**
* Aggregate function: returns the unbiased variance of the values in a group.
*
@@ -460,6 +530,14 @@ object functions extends LegacyFunctions {
*/
def var_samp(e: Column): Column = withAggregateFunction { VarianceSamp(e.expr) }
+ /**
+ * Aggregate function: returns the unbiased variance of the values in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def var_samp(columnName: String): Column = var_samp(Column(columnName))
+
/**
* Aggregate function: returns the population variance of the values in a group.
*
@@ -468,6 +546,14 @@ object functions extends LegacyFunctions {
*/
def var_pop(e: Column): Column = withAggregateFunction { VariancePop(e.expr) }
+ /**
+ * Aggregate function: returns the population variance of the values in a group.
+ *
+ * @group agg_funcs
+ * @since 1.6.0
+ */
+ def var_pop(columnName: String): Column = var_pop(Column(columnName))
+
//////////////////////////////////////////////////////////////////////////////////////////////
// Window functions
//////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
index 9c42f65bb6..b5c636d0de 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
@@ -261,6 +261,9 @@ class DataFrameAggregateSuite extends QueryTest with SharedSQLContext {
checkAnswer(
testData2.agg(stddev('a), stddev_pop('a), stddev_samp('a)),
Row(testData2ADev, math.sqrt(4 / 6.0), testData2ADev))
+ checkAnswer(
+ testData2.agg(stddev("a"), stddev_pop("a"), stddev_samp("a")),
+ Row(testData2ADev, math.sqrt(4 / 6.0), testData2ADev))
}
test("zero stddev") {
--
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