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

In late, but got here via Google, so for the sake of posterity, I'll add an alternative solution.

Another approach is to use TOP twice, with alternating orders. I don't know if it is "pure SQL", because it uses a variable in the TOP, but it works in SQL Server 2008. Here's an example I use against a table of dictionary words, if I want a random word.

SELECT TOP 1
  word
FROM (
  SELECT TOP(@idx)
    word 
  FROM
    dbo.DictionaryAbridged WITH(NOLOCK)
  ORDER BY
    word DESC
) AS D
ORDER BY
  word ASC

Of course, @idx is some randomly-generated integer that ranges from 1 to COUNT(*) on the target table, inclusively. If your column is indexed, you'll benefit from it too. Another advantage is that you can use it in a function, since NEWID() is disallowed.

Lastly, the above query runs in about 1/10 of the exec time of a NEWID()-type of query on the same table. YYMV.