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/*
* 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.expressions._
import org.apache.spark.sql.catalyst.util.TypeUtils
import org.apache.spark.sql.types._
@ExpressionDescription(
usage = "_FUNC_(x) - Returns the sum calculated from values of a group.")
case class Sum(child: Expression) extends DeclarativeAggregate {
override def children: Seq[Expression] = child :: Nil
override def nullable: Boolean = true
// Return data type.
override def dataType: DataType = resultType
override def inputTypes: Seq[AbstractDataType] =
Seq(TypeCollection(LongType, DoubleType, DecimalType))
override def checkInputDataTypes(): TypeCheckResult =
TypeUtils.checkForNumericExpr(child.dataType, "function sum")
private lazy val resultType = child.dataType match {
case DecimalType.Fixed(precision, scale) =>
DecimalType.bounded(precision + 10, scale)
case _ => child.dataType
}
private lazy val sumDataType = resultType
private lazy val sum = AttributeReference("sum", sumDataType)()
private lazy val zero = Cast(Literal(0), sumDataType)
override lazy val aggBufferAttributes = sum :: Nil
override lazy val initialValues: Seq[Expression] = Seq(
/* sum = */ Literal.create(null, sumDataType)
)
override lazy val updateExpressions: Seq[Expression] = {
if (child.nullable) {
Seq(
/* sum = */
Coalesce(Seq(Add(Coalesce(Seq(sum, zero)), Cast(child, sumDataType)), sum))
)
} else {
Seq(
/* sum = */
Add(Coalesce(Seq(sum, zero)), Cast(child, sumDataType))
)
}
}
override lazy val mergeExpressions: Seq[Expression] = {
Seq(
/* sum = */
Coalesce(Seq(Add(Coalesce(Seq(sum.left, zero)), sum.right), sum.left))
)
}
override lazy val evaluateExpression: Expression = sum
}
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