Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/6938#discussion_r34226031
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala
---
@@ -600,3 +604,146 @@ case class Logarithm(left: Expression, right:
Expression)
"""
}
}
+
+case class Round(child: Expression, scale: Expression) extends Expression
with ExpectsInputTypes {
+
+ def this(child: Expression) = {
+ this(child, Literal(0))
+ }
+
+ override def children: Seq[Expression] = Seq(child, scale)
+
+ override def nullable: Boolean = true
+
+ override def foldable: Boolean = child.foldable
+
+ override lazy val dataType: DataType = child.dataType match {
+ case DecimalType.Fixed(p, s) => DecimalType(p, _scale)
+ case t => t
+ }
+
+ override def inputTypes: Seq[AbstractDataType] = Seq(
+ // rely on precedence to implicit cast String into Double
+ TypeCollection(DecimalType, DoubleType, FloatType, LongType,
IntegerType, ShortType, ByteType),
+ TypeCollection(LongType, IntegerType, ShortType, ByteType))
+
+ override def checkInputDataTypes(): TypeCheckResult = {
+ child.dataType match {
+ case _: NumericType => // satisfy requirement
+ case dt =>
+ return TypeCheckFailure(s"Only numeric type is allowed for ROUND
function, got $dt")
+ }
+ scale match {
+ case Literal(value, LongType) =>
+ if (value.asInstanceOf[Long] < Int.MinValue ||
value.asInstanceOf[Long] > Int.MaxValue) {
+ return TypeCheckFailure("ROUND scale argument out of allowed
range")
+ }
+ case _ =>
+ if (scale.dataType.isInstanceOf[IntegralType] && scale.foldable) {
+ // TODO: How to check out of range for foldable LongType
Expression
+ // satisfy requirement
+ } else {
+ return TypeCheckFailure("Only foldable Integral Expression " +
+ s"is allowed for ROUND scale arguments, got ${child.dataType}")
--- End diff --
If you accept only IntegerType for the 2nd argument, long type will get
implicitly casted to integer by the optimizer. so I think you can just check
whether it is foldable.
also you should call super.checkInputDataTypes() to make sure the generic
type checker can run successfully, and only run the 2nd argument foldable check
after that.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
