Why I cannot use RowID in where clause but can use it in order by clause

Question

I am on SQL Server 2008.
1. If I use
SELECT (ROW_NUMBER()  over
(order by ImportId, ScenarioId, SiteID, AssetID, LocalSKUID, WEEKID, MonthID)) RowID, * 
  FROM [JnJ_Version1].[dbo].[td_Production_Week]
  order by RowID
Statement works
But
2. If I use
SELECT (ROW_NUMBER()  over
(order by ImportId, ScenarioId, SiteID, AssetID, LocalSKUID, WEEKID, MonthID)) RowID, * 
  FROM [JnJ_Version1].[dbo].[td_Production_Week]
  where  RowID > 10000
I get error, RowID is an invalid column Name why? How to correct query 2.

Answer 1

This is due to the logical evaluation order of a SELECT statement. Logically, a SELECT statement is computed in the order:
FROM (which includes JOIN)
WHERE
GROUP BY
HAVING
SELECT
ORDER BY
OFFSET
Thus, you can use what is defined in the SELECT list in the ORDER BY clause, but not in the WHERE clause.
In the case of row_number(), this has immediate repurcussions. row_number() is computed from the rows as they arrive the SELECT clause, and if you then you would filter on the value in the WHERE clause you would be going round in circles.
To do what you are looking for, you use a nested table, for instance with a CTE:
WITH numbering AS (
   SELECT (ROW_NUMBER()  over
(order by ImportId, ScenarioId, SiteID, AssetID, LocalSKUID, WEEKID, MonthID)) RowID, * 
  FROM [JnJ_Version1].[dbo].[td_Production_Week]
SELECT *
FROM   numbering
WHERE  RowID > 10000
Erland Sommarskog, SQL Server MVP, [email protected]