Hive 实现 udf row_number 以及遇到的问题

为hive的每条数据添加row_number, 首先添加行号，必须考虑到数据必须放在一个reduce中去执行。先上代码

package xx.xxxxx.hive.udf;

@UDFType(deterministic = false)
public class RowNumber extends UDF {
private static int MAX_VALUE = 50;
private static String comparedColumn[] = new String[MAX_VALUE];
private static int rowNum = 1;

public int eva luate(Object ...args) {
String columnValue[] = new String[args.length];
for (int i = 0; i < args.length; i++){
columnValue[i] = args[i].toString();
}
if (rowNum == 1) {
for (int i = 0; i < columnValue.length; i++)
comparedColumn[i] = columnValue[i];
}

for (int i = 0; i < columnValue.length; i++) {
if (!comparedColumn[i].equals(columnValue[i])) {
for (int j = 0; j < columnValue.length; j++) {
comparedColumn[j] = columnValue[j];
}
rowNum = 1;
return rowNum++;
}
}
return rowNum++;
}
}

打包jar包，并创建函数。

add jar /home/hdbatch/jars/iclickhiveudf.jar;
create temporary function row_number as 'cn.iclick.hive.udf.RowNumber';

但是用法要注意，假设我要对一个表的数据进行标注行号，两条sql语句，

create table test_tony as select row_number(1), tid from(select distinct tid from cookie where i_date=20131105)t order by tid;

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