HIVE Row_Sequence 實現列自增長

HIVE Row_Sequence 實現列自增長

package org.rowsequence;

import org.apache.Hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.udf.UDFType;
import org.apache.hadoop.io.LongWritable;

/**
 * UDFRowSequence.
 */
@Description(name = "row_sequence",
    value = "_FUNC_() - Returns a generated row sequence number starting from 1")
@UDFType(deterministic = false)
public class RowSequence extends UDF {
 private LongWritable result = new LongWritable();

  public RowSequence() {
    result.set(0);
  }

  public LongWritable evaluate() {
    result.set(result.get() + 1);
    return result;
  }
}

add jar /home/hadoop/hive_study/hive_udf/hive_udf.jar

create temporary function row_sequence as 'org.rowsequence.RowSequence';

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