SQL Kiwi (11/1/2012)
The specific answer isn't useful, but the process of writing a query to answer it surely could be. I had no idea of the correct answer so I wrote a query very similar to that given in the answer:
FROM dbo.Numbers AS n
CHAR(n) COLLATE Latin1_General_CI_AS
BETWEEN '0' AND 'Z';
The idea of QotDs that require the reader to write T-SQL code to find the answer intrigues me. If that was Tom's intention (as I suspect it was) and/or to highlight the usefulness of a Numbers table, I applaud him.
You've spotted my secondary intentions. I thought an interesting change from providing code that people could cut and paste into a query window and run would be to make them write their own code to get the answer, and that some people might learn something from being pointed at Tally tables and Jeff's excellent article again.
But I also remembered developers who were very annoyed to discover that 0 to Z contained not only what they though of as "real" consonants (including the obvious German, French, and Spanish ones), "real" (single digit integer) numerics, and "real" vowels (the usual 5 plus versions with actute, grave, circumflex, and umlaut diacritics) but a host of other things; although I'm more of a developer than a DBA myself, their reactions (for example griping about the collation being senseless, claiming that there are no useful collations or that SQL is broken if it thinks '¾' is a numeric character or that there "should" only be 72 alphanumeric characters) managed to put me firmly into the foul-tempered DBA camp. So my primary intention was to have people discover that there are a lot more than 72 alphanumeric characters in the ascii character set with the default collation.
I think the count of answers so far makes it pretty clear that most people haven't a clue what characters fall in there - two thirds of responses have chosen one of the three lowest options: 36 (26 letters of the English alphabet, forgetting that there are two cases, plus 10 numeric digits) ,43 (36 plus 7: áâéèêîô), or 62 (English alphabet with two cases, ten numeric digits). So maybe two thirds of people who have seen the question have learnt something useful - not that the answer is 139 (who cares about the exact number, as long as they can find it if they ever need it), but that the answer is quite a lot bigger than 72.