[jira] [Commented] (FLINK-4294) Allow access of composite type fields

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-4294?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15523361#comment-15523361 ] 

ASF GitHub Bot commented on FLINK-4294:
---------------------------------------

Github user twalthr commented on a diff in the pull request:

    https://github.com/apache/flink/pull/2319#discussion_r80500304
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/api/scala/table/expressionDsl.scala ---
    @@ -223,10 +223,28 @@ trait ImplicitExpressionOperations {
         */
       def toTime = Cast(expr, SqlTimeTypeInfo.TIME)
     
    -    /**
    +  /**
         * Parses a timestamp String in the form "yy-mm-dd hh:mm:ss.fff" to a SQL Timestamp.
         */
       def toTimestamp = Cast(expr, SqlTimeTypeInfo.TIMESTAMP)
    +
    +  /**
    +    * Accesses the field of a Flink composite type (such as Tuple, POJO, etc.) by name and
    +    * returns it's value.
    +    *
    +    * @param name name of the field (similar to Flink's field expressions)
    +    * @return value of the field
    +    */
    +  def getField(name: String) = GetCompositeField(expr, name)
    --- End diff --
    
    I think we don't need a wildcard. I will change this PR to support `field$subfield`.


> Allow access of composite type fields
> -------------------------------------
>
>                 Key: FLINK-4294
>                 URL: https://issues.apache.org/jira/browse/FLINK-4294
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>            Reporter: Timo Walther
>            Assignee: Timo Walther
>
> Currently all Flink CompositeTypes are treated as GenericRelDataTypes. It would be better to access individual fields of composite types, too. e.g.
> {code}
> SELECT composite.name FROM composites
> SELECT tuple.f0 FROM tuples
> 'f0.getField(0)
> {code}



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