Github user scwf commented on a diff in the pull request:
https://github.com/apache/spark/pull/6104#discussion_r30460024
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/WindowFunctionDefinition.scala ---
@@ -0,0 +1,264 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql
+
+import scala.language.implicitConversions
+
+import org.apache.spark.annotation.Experimental
+import org.apache.spark.sql.catalyst.expressions._
+
+/**
+ * :: Experimental ::
+ * A set of methods for window function definition for aggregate
expressions.
+ * For example:
+ * {{{
+ * df.select(
+ * avg("value")
+ * .over
+ * .partitionBy("k1")
+ * .orderBy("k2", "k3")
+ * .row
+ * .following(1)
+ * .toColumn.as("avg_value"),
+ * max("value")
+ * .over
+ * .partitionBy("k2")
+ * .orderBy("k3")
+ * .between
+ * .preceding(4)
+ * .following(3)
+ * .toColumn.as("max_value"))
+ * }}}
+ *
+ *
+ */
+@Experimental
+class WindowFunctionDefinition protected[sql](
+ column: Column = null,
+ partitionSpec: Seq[Expression] = Nil,
+ orderSpec: Seq[SortOrder] = Nil,
+ frame: WindowFrame = UnspecifiedFrame) {
+
+ private[sql] def newColumn(c: Column): WindowFunctionDefinition = {
+ new WindowFunctionDefinition(c, partitionSpec, orderSpec, frame)
+ }
+
+ /**
+ * Returns a new [[WindowFunctionDefinition]] partitioned by the
specified column.
+ * {{{
+ * // The following 2 are equivalent
+ * df.over.partitionBy("k1", "k2", ...)
+ * df.over.partitionBy($"K1", $"k2", ...)
+ * }}}
+ * @group window_funcs
+ */
+ @scala.annotation.varargs
+ def partitionBy(colName: String, colNames: String*):
WindowFunctionDefinition = {
+ partitionBy((colName +: colNames).map(Column(_)): _*)
+ }
+
+ /**
+ * Returns a new [[WindowFunctionDefinition]] partitioned by the
specified column. For example:
+ * {{{
+ * df.over.partitionBy($"col1", $"col2")
+ * }}}
+ * @group window_funcs
+ */
+ @scala.annotation.varargs
+ def partitionBy(cols: Column*): WindowFunctionDefinition = {
+ new WindowFunctionDefinition(column, cols.map(_.expr), orderSpec,
frame)
+ }
+
+ /**
+ * Returns a new [[WindowFunctionDefinition]] sorted by the specified
column within
+ * the partition.
+ * {{{
+ * // The following 2 are equivalent
+ * df.over.partitionBy("k1").orderBy("k2", "k3")
+ * df.over.partitionBy("k1").orderBy($"k2", $"k3")
+ * }}}
+ * @group window_funcs
+ */
+ @scala.annotation.varargs
+ def orderBy(colName: String, colNames: String*):
WindowFunctionDefinition = {
+ orderBy((colName +: colNames).map(Column(_)): _*)
+ }
+
+ /**
+ * Returns a new [[WindowFunctionDefinition]] sorted by the specified
column within
+ * the partition. For example
+ * {{{
+ * df.over.partitionBy("k1").orderBy($"k2", $"k3")
+ * }}}
+ * @group window_funcs
+ */
+ def orderBy(cols: Column*): WindowFunctionDefinition = {
+ val sortOrder: Seq[SortOrder] = cols.map { col =>
+ col.expr match {
+ case expr: SortOrder =>
+ expr
+ case expr: Expression =>
+ SortOrder(expr, Ascending)
+ }
+ }
+ new WindowFunctionDefinition(column, partitionSpec, sortOrder, frame)
+ }
+
+ /**
+ * Returns a new ranged [[WindowFunctionDefinition]]. For example:
+ * {{{
+ * df.over.partitionBy("k1").orderBy($"k2", $"k3").between
+ * }}}
+ * @group window_funcs
+ */
+ def between: WindowFunctionDefinition = {
+ new WindowFunctionDefinition(column, partitionSpec, orderSpec,
+ SpecifiedWindowFrame(RangeFrame, UnboundedPreceding,
UnboundedFollowing))
--- End diff --
Also i think this is not right, `between` not indicate the frame type is
`RangeFrame`
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