Question

我不确定这是一个错误（或只是不正确的语法）。我四处搜索，并没有在其他地方看到这个，所以我在提交错误报告之前就在这里问。

我正在尝试使用嵌套列上的Window函数。我在下面创建了一个小例子来说明问题。

import sqlContext.implicits._
import org.apache.spark.sql.functions._
import org.apache.spark.sql.expressions.Window

val data = Seq(("a", "b", "c", 3), ("c", "b", "a", 3)).toDF("A", "B", "C", "num")
  .withColumn("Data", struct("A", "B", "C")).drop("A").drop("B").drop("C")
val winSpec = Window.partitionBy("Data.A", "Data.B").orderBy($"num".desc)
data.select($"*", max("num").over(winSpec) as "max").where("num = max").drop("max").show

以上导致错误 org.apache.spark.sql.AnalysisException: resolved attribute(s) A#39,B#40 missing from num#33,Data#37 in operator !Project [num#33,Data#37,A#39,B#40]; at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$class.failAnalysis(CheckAnalysis.scala:38) at org.apache.spark.sql.catalyst.analysis.Analyzer.failAnalysis(Analyzer.scala:44) ...

如果相反这些列没有嵌套，它可以正常工作。我是否遗漏了语法，或者这是一个错误？

Answer 1

在我看来，当分析仪试图扩展*

时，你正在遇到一个错误

import sqlContext.implicits._
import org.apache.spark.sql.functions._
import org.apache.spark.sql.expressions.Window

sql("SET spark.sql.eagerAnalysis=false") // Let us see the error even though we are constructing an invalid tree

val data = Seq(("a", "b", "c", 3), ("c", "b", "a", 3)).toDF("A", "B", "C", "num")
  .withColumn("Data", struct("A", "B", "C"))
  .drop("A")
  .drop("B")
  .drop("C")

val winSpec = Window.partitionBy("Data.A", "Data.B").orderBy($"num".desc)
data.select($"*", max("num").over(winSpec) as "max").explain(true)

通过关闭急切分析（以便我们可以在不抛出错误的情况下调用解释），您可以看到“*”正在扩展以包含实际不可用的列：

== Parsed Logical Plan ==
'Project [*,'max('num) windowspecdefinition('Data.A,'Data.B,'num DESC,UnspecifiedFrame) AS max#64928]
+- Project [num#64926,Data#64927]
   +- Project [C#64925,num#64926,Data#64927]
      +- Project [B#64924,C#64925,num#64926,Data#64927]
         +- Project [A#64923,B#64924,C#64925,num#64926,struct(A#64923,B#64924,C#64925) AS Data#64927]
            +- Project [_1#64919 AS A#64923,_2#64920 AS B#64924,_3#64921 AS C#64925,_4#64922 AS num#64926]
               +- LocalRelation [_1#64919,_2#64920,_3#64921,_4#64922], [[a,b,c,3],[c,b,a,3]]

== Analyzed Logical Plan ==
num: int, Data: struct<A:string,B:string,C:string>, max: int
Project [num#64926,Data#64927,max#64928]
+- Project [num#64926,Data#64927,A#64932,B#64933,max#64928,max#64928]
   +- Window [num#64926,Data#64927,A#64932,B#64933], [HiveWindowFunction#org.apache.hadoop.hive.ql.udf.generic.GenericUDAFMax(num#64926) windowspecdefinition(A#64932,B#64933,num#64926 DESC,RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS max#64928], [A#64932,B#64933], [num#64926 DESC]
      +- !Project [num#64926,Data#64927,A#64932,B#64933]
         +- Project [num#64926,Data#64927]
            +- Project [C#64925,num#64926,Data#64927]
               +- Project [B#64924,C#64925,num#64926,Data#64927]
                  +- Project [A#64923,B#64924,C#64925,num#64926,struct(A#64923,B#64924,C#64925) AS Data#64927]
                     +- Project [_1#64919 AS A#64923,_2#64920 AS B#64924,_3#64921 AS C#64925,_4#64922 AS num#64926]
                        +- LocalRelation [_1#64919,_2#64920,_3#64921,_4#64922], [[a,b,c,3],[c,b,a,3]]

我在这里提交了这个：https://issues.apache.org/jira/browse/SPARK-12989。如果您手动列出列而不是使用*作为解决方法。

具有嵌套列

1 个答案: