HIVE Row_Sequence 实现列自增长

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';