spark Max 源码

2022-10-20
浏览 (307)

spark Max 代码

文件路径：/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Max.scala

/*
 * 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.catalyst.expressions.aggregate

import org.apache.spark.sql.catalyst.analysis.TypeCheckResult
import org.apache.spark.sql.catalyst.dsl.expressions._
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.trees.UnaryLike
import org.apache.spark.sql.catalyst.util.TypeUtils
import org.apache.spark.sql.types._

@ExpressionDescription(
  usage = "_FUNC_(expr) - Returns the maximum value of `expr`.",
  examples = """
    Examples:
      > SELECT _FUNC_(col) FROM VALUES (10), (50), (20) AS tab(col);
       50
  """,
  group = "agg_funcs",
  since = "1.0.0")
case class Max(child: Expression) extends DeclarativeAggregate with UnaryLike[Expression] {

  override def nullable: Boolean = true

  // Return data type.
  override def dataType: DataType = child.dataType

  override def checkInputDataTypes(): TypeCheckResult =
    TypeUtils.checkForOrderingExpr(child.dataType, "function max")

  private lazy val max = AttributeReference("max", child.dataType)()

  override lazy val aggBufferAttributes: Seq[AttributeReference] = max :: Nil

  override lazy val initialValues: Seq[Literal] = Seq(
    /* max = */ Literal.create(null, child.dataType)
  )

  override lazy val updateExpressions: Seq[Expression] = Seq(
    /* max = */ greatest(max, child)
  )

  override lazy val mergeExpressions: Seq[Expression] = {
    Seq(
      /* max = */ greatest(max.left, max.right)
    )
  }

  override lazy val evaluateExpression: AttributeReference = max

  override protected def withNewChildInternal(newChild: Expression): Max = copy(child = newChild)
}

相关信息

spark 源码目录

相关文章

spark AnyValue 源码

spark ApproxCountDistinctForIntervals 源码

spark ApproximatePercentile 源码

spark Average 源码

spark BloomFilterAggregate 源码

spark CentralMomentAgg 源码

spark Corr 源码

spark Count 源码

spark CountIf 源码

spark CountMinSketchAgg 源码

0 赞

所属分类： 前端技术
本文标签：
版权声明： 原创文章如转载，请注明本文链接: https://www.seaxiang.com/blog/044292a9ccfc4b0ba26c38ebac899a6f

热门推荐

1、直接访问google.com
2、 - 优质文章
3、 gate.io
4、 harmony 鸿蒙hdc使用指导
5、 harmony 鸿蒙ArkUI组件（ArkTS）开发常见问题
6、 harmony 鸿蒙初识ArkTS语言
7、 golang
8、 flink kafka connector scan.startup.mode 的几个选项
9、 openharmony
10、 Vue中input框自动聚焦

Loading...