Question

I need to add an auto generated auto-increment id to a query results.
For example, for the query

SELECT TOP 3 Users.Reputation FROM Users ORDER BY 1 DESC

Instead of getting

• 101
• 100
• 99

I want to get

• 1, 101
• 2, 100
• 3, 99

How can I do it?

Answer 1

How about:

;WITH CTE AS 
(SELECT
    RowNum = ROW_NUMBER() OVER(ORDER BY Reputation DESC),
    Users.Reputation
 FROM
    Users
)
SELECT TOP 3
    RowNum, Reputation
FROM
    CTE
ORDER BY  
    RowNum

This is a CTE (Common Table Expression) available in SQL Server 2005 and newer, combined with the ROW_NUMBER() ranking function, also available in 2005 and newer.

It creates an “on-the-fly” view for just the next statement and allows to do some extra processing first, before selecting. The ROW_NUMBER() just adds a consecutive number to each row in the order defined in the OVER (ORDER BY ....) clause. So the first row gets #1, the second #2 and so on.

Read more about CTE’s here: MSDN – Using Common Table Expressions

Read more about ROW_NUMBER and other ranking functions here: MSDN ROW_NUMBER