SQL Error of Undefined Column

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.