viirya commented on a change in pull request #28996: URL: https://github.com/apache/spark/pull/28996#discussion_r449904117
########## File path: sql/core/src/test/scala/org/apache/spark/sql/DataFrameSetOperationsSuite.scala ########## @@ -506,4 +506,23 @@ class DataFrameSetOperationsSuite extends QueryTest with SharedSparkSession { check(lit(2).cast("int"), $"c" === 2, Seq(Row(1, 1, 2, 0), Row(1, 1, 2, 1))) check(lit(2).cast("int"), $"c" =!= 2, Seq()) } + + test("SPARK-29358: Make unionByName optionally fill missing columns with nulls") { + withSQLConf(SQLConf.ALLOW_MISSING_COLUMNS_IN_UNION_BY_NAME.key -> "true") { + var df1 = Seq(1, 2, 3).toDF("a") + var df2 = Seq(3, 1, 2).toDF("b") + val df3 = Seq(2, 3, 1).toDF("c") + val unionDf = df1.unionByName(df2.unionByName(df3)) + checkAnswer(unionDf, + Row(1, null, null) :: Row(2, null, null) :: Row(3, null, null) :: // df1 + Row(null, 3, null) :: Row(null, 1, null) :: Row(null, 2, null) :: // df2 + Row(null, null, 2) :: Row(null, null, 3) :: Row(null, null, 1) :: Nil // df3 + ) + + df1 = Seq((1, 2)).toDF("a", "c") + df2 = Seq((3, 4, 5)).toDF("a", "b", "c") + checkAnswer(df1.unionByName(df2), Review comment: `df2.unionByName(df1)` is also okay. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org