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Posted to issues@flink.apache.org by "hehuiyuan (Jira)" <ji...@apache.org> on 2020/01/16 11:01:00 UTC

[jira] [Comment Edited] (FLINK-15610) How to achieve the udf that the number of return column is uncertain

    [ https://issues.apache.org/jira/browse/FLINK-15610?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17016808#comment-17016808 ] 

hehuiyuan edited comment on FLINK-15610 at 1/16/20 11:00 AM:
-------------------------------------------------------------

[~lzljs3620320]

I have achieved by constructor， but it is't  convenient.

If the udf is used more than once and output column's number is different,  I need to register  many times.
{code:java}
public int columnNumber;

public MultiKeyValueUdf(String columnNumber) {
  this.columnNumber = Integer.valueOf(columnNumber);
}

@Override
public TypeInformation getResultType() {
  TypeInformation[] typeInformations = new TypeInformation[columnNumber];
  for(int i = 0 ; i < columnNumber;i++){
    typeInformations[i] = Types.STRING();
  }
  return Types.ROW(typeInformations);
}
{code}
 


was (Author: hehuiyuan):
I have achieved by constructor， but it is't  convenient.

If the udf is used more than once and output column's number is different,  I need to register  many times.
{code:java}

public int columnNumber;

public MultiKeyValueUdf(String columnNumber) {
  this.columnNumber = Integer.valueOf(columnNumber);
}

@Override
public TypeInformation getResultType() {
  TypeInformation[] typeInformations = new TypeInformation[columnNumber];
  for(int i = 0 ; i < columnNumber;i++){
    typeInformations[i] = Types.STRING();
  }
  return Types.ROW(typeInformations);
}
{code}
 

> How to achieve the udf that the number of return column is uncertain 
> ---------------------------------------------------------------------
>
>                 Key: FLINK-15610
>                 URL: https://issues.apache.org/jira/browse/FLINK-15610
>             Project: Flink
>          Issue Type: Wish
>          Components: Table SQL / API
>            Reporter: hehuiyuan
>            Priority: Major
>
> For example:[https://help.aliyun.com/knowledge_detail/98948.html?spm=a2c4g.11186631.2.3.21b81761QhpBte]
>  
> {code:java}
> SELECT c1, c2 
> FROM T1, lateral table(MULTI_KEYVALUE(str, split1, split2, key1, key2)) 
> as T(c1, c2)
> SELECT c1, c2, c3 
> FROM T1, lateral table(MULTI_KEYVALUE(str, split1, split2, key1, key2, key3)) 
> as T(c1, c2, c3)
> {code}
> For Tablefunction:
> {code:java}
> public TypeInformation<Row> getResultType() {
>   return Types.ROW(Types.STRING(),Types.STRING());
> }
> {code}
> The retrun type of  `getResultType` is `TypeInformation<Row>`,i want to achieve the size of row is not fixed.
>  



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