How to get only the max row number row of record?

Question

Below query results the record as follows ..

How to get only the max row number row of record? I have run this query for over 20,000 records to identify duplication and get the most recent date and its number of processed (RowNumber).

select [FileName], ProcessDate,
ROW_NUMBER() over (partition by [FileName] order by [FileName] desc) RowNumber 
from  StagingTable
where filename = 'abc.txt'

Answer 1

Are you looking for a filter?

select s.*
from (select [FileName], ProcessDate,
             ROW_NUMBER() over (partition by [FileName] order by ProcessDate desc) as RowNumber 
      from StagingTable
      where filename = 'abc.txt'
     ) s
where RowNumber = 1;

Note that the ORDER BY has changed.

If you want the total count as well, then add then in as an additional column:

select s.*
from (select [FileName], ProcessDate,
             count(*) over (partition by filename) as cnt,
             ROW_NUMBER() over (partition by [FileName] order by ProcessDate desc) as RowNumber 
      from StagingTable
      where filename = 'abc.txt'
     ) s
where RowNumber = 1;

Answer 2

Given your logic, there does not seem to be a maximum row number. Or is the row numbering tied to another field than ProcessDate ?

As far as I understand your problem, I would just use the following query:

SELECT [FileName], MAX([ProcessDate]) AS [ProcessDate], COUNT(*) AS [Count]
FROM [StagingTable]
GROUP BY [FileName]

Answer 3

Your query has an error: in the OrderBy you wrote FileName, but I guess you're using the date.

You can double on the ROW_NUMBER() columns:

WITH VersionSorting AS (
  select
    [FileName],
    ProcessDate,
    ROW_NUMBER() over (partition by [FileName] order by [ProcessDate] ASC) FileVersion,
    ROW_NUMBER() over (partition by [FileName] order by [ProcessDate] DESC) FileVersionInv
  from  StagingTable
)
SELECT FileName, ProcessDate, FileVersion
FROM VersionSorting
WHERE FileVersionInv = 1
-- AND FileName = 'abc.txt'