How to request a random row in SQL?

Question

How can I request a random row (or as close to truly random as is possible) in pure SQL?

Answer 1

For SQL Server 2005 and above, extending @GreyPanther's answer for the cases when num_value has not continuous values. This works too for cases when we have not evenly distributed datasets and when num_value is not a number but a unique identifier.

WITH CTE_Table (SelRow, num_value) 
AS 
(
    SELECT ROW_NUMBER() OVER(ORDER BY ID) AS SelRow, num_value FROM table
) 

SELECT * FROM table Where num_value = ( 
    SELECT TOP 1 num_value FROM CTE_Table  WHERE SelRow >= RAND() * (SELECT MAX(SelRow) FROM CTE_Table)
)