Select Row number in postgres

Question

How to select row number in postgres.

I tried this:

select
    row_number() over (ORDER BY cgcode_odc_mapping_id)as rownum,
    cgcode_odc_mapping_id
          


        

Answer 1

SELECT tab.*,
    row_number() OVER () as rnum
  FROM tab;

Here's the relevant section in the docs.

P.S. This, in fact, fully matches the answer in the referenced question.