How to select standard deviation within a row? (in SQL - or R :)

Question

I wonder whether there is a way to select the standard deviation from several integer fields in MySQL within the same row. Obviously, if I use

Answer 1

for simplicity, assume you have n columns, named A, B, C .... :

SELECT SQRT(  
  (A*A + B*B + C*C + ...)/n  - (A+B+C+...)*(A+B+C+...)/n/n) AS sd
  FROM table;