[
https://issues.apache.org/jira/browse/SPARK-19536?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15860816#comment-15860816
]
Hyukjin Kwon commented on SPARK-19536:
--------------------------------------
Thank you for kindly adding a link.
> Improve capability to merge SQL data types
> ------------------------------------------
>
> Key: SPARK-19536
> URL: https://issues.apache.org/jira/browse/SPARK-19536
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 2.1.0
> Reporter: koert kuipers
> Priority: Minor
>
> spark's union/merging of compatible types seems kind of weak. it works on
> basic types in the top level record, but it fails for nested records, maps,
> arrays, etc.
> i would like to improve this.
> for example i get errors like this:
> {noformat}
> org.apache.spark.sql.AnalysisException: Union can only be performed on tables
> with the compatible column types. StructType(StructField(_1,StringType,true),
> StructField(_2,IntegerType,false)) <>
> StructType(StructField(_1,StringType,true), StructField(_2,LongType,false))
> at the first column of the second table
> {noformat}
> some examples that do work:
> {noformat}
> scala> Seq(1, 2, 3).toDF union Seq(1L, 2L, 3L).toDF
> res2: org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] = [value: bigint]
> scala> Seq((1,"x"), (2,"x"), (3,"x")).toDF union Seq((1L,"x"), (2L,"x"),
> (3L,"x")).toDF
> res3: org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] = [_1: bigint,
> _2: string]
> {noformat}
> what i would also expect to work but currently doesn't:
> {noformat}
> scala> Seq((Seq(1),"x"), (Seq(2),"x"), (Seq(3),"x")).toDF union
> Seq((Seq(1L),"x"), (Seq(2L),"x"), (Seq(3L),"x")).toDF
> scala> Seq((1,("x",1)), (2,("x",2)), (3,("x",3))).toDF union
> Seq((1L,("x",1L)), (2L,("x",2L)), (3L,("x", 3L))).toDF
> {noformat}
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
