Question

I’m using the ROW_NUMBER() function in SQL Server to create a new column called RowNumber.

But when I later in the same query reference this new field in the WHERE statement I get this error, even though the field should be an integer:

Conversion failed when converting the varchar value ‘RowNumber’ to data type int

Here is my query:

SELECT 
   ROW_NUMBER() OVER(PARTITION BY c.Node_base ORDER BY sum(c.Score) DESC) AS "RowNumber",  
   c.Node_base, c.Node_forslag, sum(Score)
FROM         
   t_input as c
WHERE 'RowNumber' < 11
GROUP BY c.Node_base, c.Node_forslag
ORDER BY c.Node_base desc

Answer 1

You can’t reference a calculated column from the SELECT clause in the WHERE clause – and even if you could, single quotes introduce a string literal, rather than a column reference. Use a CTE or subquery.

;With Sums as (
    SELECT c.Node_base, c.Node_forslag,SUM(c.Score) as TotScore
    FROM t_input as c
    GROUP BY c.Node_base, c.Node_forslag
), NumberedRows as (
   SELECT *,ROW_NUMBER() OVER(PARTITION BY Node_base ORDER BY TotScore DESC) AS RowNumber
   FROM Sums
)
select * from NumberedRows
WHERE RowNumber <11
order by Node_base desc

There’s no need to quote the name RowNumber at all – it’s not a reserved word, and it contains no special characters.