[ https://issues.apache.org/jira/browse/SPARK-37575 ]
Guo Wei deleted comment on SPARK-37575: --------------------------------- was (Author: wayne guo): I also found that if emptyValueInRead set to "\"\"", reading csv data as show below: {noformat} name,brand,comment tesla,,""{noformat} The final result shows as follows: ||name||brand||comment|| |tesla|null|""| But, the expected result should be: ||name||brand||comment|| |tesla|null| | > Null values are saved as quoted empty Strings "" rather than nothing > -------------------------------------------------------------------- > > Key: SPARK-37575 > URL: https://issues.apache.org/jira/browse/SPARK-37575 > Project: Spark > Issue Type: Bug > Components: SQL > Affects Versions: 2.4.0, 3.2.0 > Reporter: Guo Wei > Priority: Major > > As mentioned in sql migration > guide([https://spark.apache.org/docs/latest/sql-migration-guide.html#upgrading-from-spark-sql-23-to-24]), > {noformat} > Since Spark 2.4, empty strings are saved as quoted empty strings "". In > version 2.3 and earlier, empty strings are equal to null values and do not > reflect to any characters in saved CSV files. For example, the row of "a", > null, "", 1 was written as a,,,1. Since Spark 2.4, the same row is saved as > a,,"",1. To restore the previous behavior, set the CSV option emptyValue to > empty (not quoted) string.{noformat} > > But actually, both empty strings and null values are saved as quoted empty > Strings "" rather than "" (for empty strings) and nothing(for null values)。 > code: > {code:java} > val data = List("spark", null, "").toDF("name") > data.coalesce(1).write.csv("spark_csv_test") > {code} > actual result: > {noformat} > line1: spark > line2: "" > line3: ""{noformat} > expected result: > {noformat} > line1: spark > line2: > line3: "" > {noformat} -- This message was sent by Atlassian Jira (v8.20.1#820001) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org