SQL Error of Undefined Column - sql

Question

SELECT
Stockmain.VRNOA,
item.description as item_description,
party.name as party_name,
stockmain.vrdate,
stockdetail.qty,
stockdetail.rate,
stockdetail.amount,
ROW_NUMBER() OVER (ORDER BY VRDATE) AS RowNum
FROM StockMain
INNER JOIN StockDetail
ON StockMain.stid = StockDetail.stid
INNER JOIN party
ON party.party_id = stockmain.party_id
INNER JOIN item
ON item.item_id = stockdetail.item_id
WHERE stockmain.etype='purchase' AND RowNum BETWEEN 1 and (1 + 100)
ORDER BY VRDATE DESC
I am trying to execute this query on SQL Server and it keeps giving this error
Invalid column name 'RowNum'.
Can anyone please have a look and tell me what I'm doing wrong here?
Update
The query I was originally using was
SELECT
*
FROM (
SELECT
Stockmain.VRNOA,
item.description as item_description,
party.name as party_name,
stockmain.vrdate,
stockdetail.qty,
stockdetail.rate,
stockdetail.amount,
ROW_NUMBER() OVER (ORDER BY VRDATE DESC) AS RowNum --< ORDER BY
FROM StockMain
INNER JOIN StockDetail
ON StockMain.stid = StockDetail.stid
INNER JOIN party
ON party.party_id = stockmain.party_id
INNER JOIN item
ON item.item_id = stockdetail.item_id
WHERE stockmain.etype='purchase'
) AS MyDerivedTable
WHERE
MyDerivedTable.RowNum BETWEEN 1 and 5
but the data in the data is immense and using this query slows down the retrieval process, so I modified the query as above and now I'm getting this error of undefined column.

Answer 1

It looks like you're trying to perform a paging operation, or at least a query that is greatly simplified using the new paging operators in SQL Server 2012, OFFSET and FETCH:
SELECT
Stockmain.VRNOA,
item.description as item_description,
party.name as party_name,
stockmain.vrdate,
stockdetail.qty,
stockdetail.rate,
stockdetail.amount
FROM StockMain
INNER JOIN StockDetail
ON StockMain.stid = StockDetail.stid
INNER JOIN party
ON party.party_id = stockmain.party_id
INNER JOIN item
ON item.item_id = stockdetail.item_id
WHERE stockmain.etype='purchase'
ORDER BY VRDATE DESC
OFFSET 0 ROWS
FETCH NEXT 100 ROWS ONLY
For more information, please see the following: http://www.dbadiaries.com/new-t-sql-features-in-sql-server-2012-offset-and-fetch

Answer 2

Put it in a subquery, the ROW_NUMBER() can't be used in the WHERE clause, not to mention you can't use aliases created in the SELECT list in the WHERE clause:
SELECT *
FROM (SELECT
Stockmain.VRNOA,
item.description as item_description,
party.name as party_name,
stockmain.vrdate,
stockdetail.qty,
stockdetail.rate,
stockdetail.amount,
ROW_NUMBER() OVER (ORDER BY VRDATE) AS RowNum
FROM StockMain
INNER JOIN StockDetail
ON StockMain.stid = StockDetail.stid
INNER JOIN party
ON party.party_id = stockmain.party_id
INNER JOIN item
ON item.item_id = stockdetail.item_id
WHERE etype='purchase'
)sub
WHERE RowNum BETWEEN 1 and (1 + 100)
ORDER BY VRDATE DESC
Update: After seeing your update it's clear you've got a working query but are trying to optimize it, even if you could move the ROW_NUMBER() inside the main query it wouldn't improve performance, it still has to perform the intensive ORDER on the full data set. Indexing VRDATE will help.

Answer 3

This is a situation where you need to use a memory table or a temp table;
to use a memory table;
DECLARE #Table TABLE(ROWID int identity,<all your columns>)
INSERT INTO #Table (<your columns>)
SELECT
Stockmain.VRNOA,
item.description as item_description,
party.name as party_name,
stockmain.vrdate,
stockdetail.qty,
stockdetail.rate,
stockdetail.amount,
ROW_NUMBER() OVER (ORDER BY VRDATE) AS RowNum
FROM StockMain
INNER JOIN StockDetail
ON StockMain.stid = StockDetail.stid
INNER JOIN party
ON party.party_id = stockmain.party_id
INNER JOIN item
ON item.item_id = stockdetail.item_id
WHERE etype='purchase'
SELECT <columns you need> FROM #Table
If you use a #temp table, make sure to drop it after the SELECT statement.