Github user marmbrus commented on a diff in the pull request:
https://github.com/apache/spark/pull/1151#discussion_r14051147
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala ---
@@ -204,3 +204,18 @@ case class ExistingRdd(output: Seq[Attribute], rdd:
RDD[Row]) extends LeafNode {
override def execute() = rdd
}
+/**
+ * :: DeveloperApi ::
+ * This operator support the substract function .Return an table with the
elements from `this` that are not in `other`.
+ */
+@DeveloperApi
+case class Except(children: Seq[SparkPlan])(@transient sc: SparkContext)
extends SparkPlan {
--- End diff --
Maybe name this operators `Subtract`. In general most of the
catalyst/spark SQL operators are named after the relational operations they are
performing.
If you aren't using `sc` I'd drop it and the `otherCopyArgs`.
Also, lets enforce the constraint from the TODO below using the typesystem.
Just have the operator be a BinaryNode with two children, `left` and `right`.
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