Github user ueshin commented on a diff in the pull request: https://github.com/apache/spark/pull/21050#discussion_r185739950 --- Diff: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/collectionOperations.scala --- @@ -1059,3 +1059,96 @@ case class Flatten(child: Expression) extends UnaryExpression { override def prettyName: String = "flatten" } + +/** + * Removes duplicate values from the array. + */ +@ExpressionDescription( + usage = "_FUNC_(array) - Removes duplicate values from the array.", + examples = """ + Examples: + > SELECT _FUNC_(array(1, 2, 3, null, 3)); + [1,2,3,null] + """, since = "2.4.0") +case class ArrayDistinct(child: Expression) + extends UnaryExpression with ExpectsInputTypes { + + override def inputTypes: Seq[AbstractDataType] = Seq(ArrayType) + + override def dataType: DataType = child.dataType + + override def nullSafeEval(array: Any): Any = { + val elementType = child.dataType.asInstanceOf[ArrayType].elementType + val data = array.asInstanceOf[ArrayData].toArray[AnyRef](elementType).distinct --- End diff -- Do we need to keep the element order? If so, does `distinct` keep the order?
--- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org