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https://issues.apache.org/jira/browse/SPARK-23157?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16343962#comment-16343962
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Henry Robinson commented on SPARK-23157:
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[~kretes] - I can see an argument for the behaviour you're describing, but
that's not the way the API is apparently intended. Like Sean says, there are
way too many ways to shoot yourself in the foot if you can stitch together
arbitrary datasets like this if the Datasets are column-wise incompatible, and
allowing the relatively small subset of cases where it would work would lead to
a more confusing API, IMO.
The documentation for {{withColumn()}} could be updated to make this clearer;
if I get a moment today I'll submit a PR.
> withColumn fails for a column that is a result of mapped DataSet
> ----------------------------------------------------------------
>
> Key: SPARK-23157
> URL: https://issues.apache.org/jira/browse/SPARK-23157
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.2.1
> Reporter: Tomasz Bartczak
> Priority: Minor
>
> Having
> {code:java}
> case class R(id: String)
> val ds = spark.createDataset(Seq(R("1")))
> {code}
> This works:
> {code}
> scala> ds.withColumn("n", ds.col("id"))
> res16: org.apache.spark.sql.DataFrame = [id: string, n: string]
> {code}
> but when we map over ds it fails:
> {code}
> scala> ds.withColumn("n", ds.map(a => a).col("id"))
> org.apache.spark.sql.AnalysisException: resolved attribute(s) id#55 missing
> from id#4 in operator !Project [id#4, id#55 AS n#57];;
> !Project [id#4, id#55 AS n#57]
> +- LocalRelation [id#4]
> at
> org.apache.spark.sql.catalyst.analysis.CheckAnalysis$class.failAnalysis(CheckAnalysis.scala:39)
> at
> org.apache.spark.sql.catalyst.analysis.Analyzer.failAnalysis(Analyzer.scala:91)
> at
> org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$checkAnalysis$1.apply(CheckAnalysis.scala:347)
> at
> org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$checkAnalysis$1.apply(CheckAnalysis.scala:78)
> at
> org.apache.spark.sql.catalyst.trees.TreeNode.foreachUp(TreeNode.scala:127)
> at
> org.apache.spark.sql.catalyst.analysis.CheckAnalysis$class.checkAnalysis(CheckAnalysis.scala:78)
> at
> org.apache.spark.sql.catalyst.analysis.Analyzer.checkAnalysis(Analyzer.scala:91)
> at
> org.apache.spark.sql.execution.QueryExecution.assertAnalyzed(QueryExecution.scala:52)
> at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:67)
> at
> org.apache.spark.sql.Dataset.org$apache$spark$sql$Dataset$$withPlan(Dataset.scala:2884)
> at org.apache.spark.sql.Dataset.select(Dataset.scala:1150)
> at org.apache.spark.sql.Dataset.withColumn(Dataset.scala:1905)
> ... 48 elided
> {code}
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