ROW_NUMBER () OVER in impala

I have a use case where I need to use ROW_NUMBER () over PARTITION: Something like:

SELECT
  Column1 , Column 2
  ROW_NUMBER() OVER (
    PARTITION BY ACCOUNT_NUM
    ORDER BY FREQ, MAN, MODEL) as LEVEL
FROM
  TEST_TABLE

      

I need a workaround for this in Impala. Unfortunately Impala does not support subqueries, nor does it support ROW_NUMBER () OVER functionality. Thank you for your help.

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4 answers


Impala is pretty limited for this type of query. With some assumptions, this query is possible:

  • The four columns in a split clause are never NULL

  • The four columns in the split clause uniquely identify the row


The request is pretty ugly and expensive:

select tt.column1, tt.column2, count(*) as level
from test_table tt join
     test_table tt2
     on tt.account_num = tt2.account_num and
        (tt2.freq < tt.freq or
         tt2.freq = tt.freq and tt2.man < t.man or
         tt2.freq = tt.freq and tt2.man = t.man and tt2.model <= t.model
        )
group by tt.column1, tt.column2, tt.account_num, tt.freq, tt.man, tt.model;

      

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ROW_NUMBER () OVER PARTITION was added in CDH 5.2:

https://www.cloudera.com/documentation/enterprise/latest/topics/impala_analytic_functions.html#row_number



ROW_NUMBER() OVER([partition_by_clause] order_by_clause)

      

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Impala now supports conspiracy. The syntax is the same as in the question.

SELECT
  Column1 , Column 2
  ROW_NUMBER() OVER (
    PARTITION BY ACCOUNT_NUM
    ORDER BY FREQ, MAN, MODEL) as LEVEL
FROM
  TEST_TABLE

      

Impala documentation: https://www.cloudera.com/documentation/enterprise/5-6-x/topics/impala_analytic_functions.html#over

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Impala supports subqueries. And in brackets, and with a with

function with

.

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