From 162d04a30e38bb83d35865679145f8ea80b84c26 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dongjoon@apache.org>
Date: Tue, 19 Jul 2016 10:28:17 -0700
Subject: [PATCH] [SPARK-16602][SQL] `Nvl` function should support
numeric-string cases
## What changes were proposed in this pull request?
`Nvl` function should support numeric-straing cases like Hive/Spark1.6. Currently, `Nvl` finds the tightest common types among numeric types. This PR extends that to consider `String` type, too.
```scala
- TypeCoercion.findTightestCommonTypeOfTwo(left.dataType, right.dataType).map { dtype =>
+ TypeCoercion.findTightestCommonTypeToString(left.dataType, right.dataType).map { dtype =>
```
**Before**
```scala
scala> sql("select nvl('0', 1)").collect()
org.apache.spark.sql.AnalysisException: cannot resolve `nvl("0", 1)` due to data type mismatch:
input to function coalesce should all be the same type, but it's [string, int]; line 1 pos 7
```
**After**
```scala
scala> sql("select nvl('0', 1)").collect()
res0: Array[org.apache.spark.sql.Row] = Array([0])
```
## How was this patch tested?
Pass the Jenkins tests.
Author: Dongjoon Hyun <dongjoon@apache.org>
Closes #14251 from dongjoon-hyun/SPARK-16602.
---
.../sql/catalyst/analysis/TypeCoercion.scala | 2 +-
.../catalyst/expressions/nullExpressions.scala | 2 +-
.../catalyst/expressions/NullFunctionsSuite.scala | 15 +++++++++++++++
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
index baec6d14a2..9a040f8644 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/TypeCoercion.scala
@@ -100,7 +100,7 @@ object TypeCoercion {
}
/** Similar to [[findTightestCommonType]], but can promote all the way to StringType. */
- private def findTightestCommonTypeToString(left: DataType, right: DataType): Option[DataType] = {
+ def findTightestCommonTypeToString(left: DataType, right: DataType): Option[DataType] = {
findTightestCommonTypeOfTwo(left, right).orElse((left, right) match {
case (StringType, t2: AtomicType) if t2 != BinaryType && t2 != BooleanType => Some(StringType)
case (t1: AtomicType, StringType) if t1 != BinaryType && t1 != BooleanType => Some(StringType)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullExpressions.scala
index 523fb05397..1c18265e0f 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullExpressions.scala
@@ -134,7 +134,7 @@ case class Nvl(left: Expression, right: Expression) extends RuntimeReplaceable {
override def replaceForTypeCoercion(): Expression = {
if (left.dataType != right.dataType) {
- TypeCoercion.findTightestCommonTypeOfTwo(left.dataType, right.dataType).map { dtype =>
+ TypeCoercion.findTightestCommonTypeToString(left.dataType, right.dataType).map { dtype =>
copy(left = Cast(left, dtype), right = Cast(right, dtype))
}.getOrElse(this)
} else {
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/NullFunctionsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/NullFunctionsSuite.scala
index ace6c15dc8..712fe35f47 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/NullFunctionsSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/NullFunctionsSuite.scala
@@ -77,6 +77,21 @@ class NullFunctionsSuite extends SparkFunSuite with ExpressionEvalHelper {
}
}
+ test("SPARK-16602 Nvl should support numeric-string cases") {
+ val intLit = Literal.create(1, IntegerType)
+ val doubleLit = Literal.create(2.2, DoubleType)
+ val stringLit = Literal.create("c", StringType)
+ val nullLit = Literal.create(null, NullType)
+
+ assert(Nvl(intLit, doubleLit).replaceForTypeCoercion().dataType == DoubleType)
+ assert(Nvl(intLit, stringLit).replaceForTypeCoercion().dataType == StringType)
+ assert(Nvl(stringLit, doubleLit).replaceForTypeCoercion().dataType == StringType)
+
+ assert(Nvl(nullLit, intLit).replaceForTypeCoercion().dataType == IntegerType)
+ assert(Nvl(doubleLit, nullLit).replaceForTypeCoercion().dataType == DoubleType)
+ assert(Nvl(nullLit, stringLit).replaceForTypeCoercion().dataType == StringType)
+ }
+
test("AtLeastNNonNulls") {
val mix = Seq(Literal("x"),
Literal.create(null, StringType),
--
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