viirya commented on a change in pull request #28133: [SPARK-31156][SQL] DataFrameStatFunctions API to be consistent with respect to Column type URL: https://github.com/apache/spark/pull/28133#discussion_r404541728
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/stat/FrequentItems.scala ########## @@ -66,6 +68,19 @@ object FrequentItems extends Logging { } } + /** Helper function to resolve column to expr (if not yet) */ + // TODO: it might be helpful to have this helper in Dataset.scala, + // e.g. `drop` function uses exactly the same flow to deal with + // `Column` arguments + private def resolveColumn(df: DataFrame, col: Column): Column = { + col match { + case Column(u: UnresolvedAttribute) => + Column(df.queryExecution.analyzed.resolveQuoted( + u.name, df.sparkSession.sessionState.analyzer.resolver).getOrElse(u)) + case Column(_expr: Expression) => col + } + } Review comment: The problem with Column is, it can contain an unresolved expression, for example `UnresolvedAttribute + UnresolvedAttribute ...`. When we are allowed to use column name only, we can rely on `df.resolve(colName)` to resolve it. Once you extend to Column, you cannot do the same check as before. ---------------------------------------------------------------- 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 With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org