MySQL 5.1: Measuring #queries/sec. using information_schema.GLOBAL_STATUS

MySQL 5.1 offers new information tables such as GLOBAL_STATUS. This can be used to report certain performance metrics, such as the number of queries processed per second:

SELECT MAX(                                         -- use MAX to force aggregation
           IF(variable_name='Questions'             -- no. of queries sent to server
           ,   CAST(variable_value AS unsigned)     -- make integer value
           ,   0                                    -- ignore if not 'Questions'
           )
       )
/                                                   -- divide by
       MAX(                                         -- use MAX to force aggregation
           IF(variable_name='Uptime'                -- no. of seconds the server is up
           ,   CAST(variable_value AS unsigned)     -- make integer value
           ,   0                                    -- ignore if not 'Uptime'
           )
       ) AS queries_per_second
FROM   information_schema.GLOBAL_STATUS 
WHERE  variable_name in ('Questions', 'Uptime');

(This snippet is maintained on MySQL Forge)

This query could have been solved in a number of other ways involving subqueries, for example like this:

SELECT (SELECT CAST(variable_value AS unsigned)
        FROM   information_schema.GLOBAL_STATUS
        WHERE  variable_name = 'Questions') 
/      (SELECT CAST(variable_value AS unsigned)
        FROM   information_schema.GLOBAL_STATUS
        WHERE  variable_name = 'Uptime')  as queries_per_second

For now I'm sticking to my original snippet. The disadvantage to this approach is that it requires a hack to force aggregation of all rows from GLOBAL_STATUS to one single row (using MAX), as well as some conditional expressions.

The disadvantage of a using subqueries is that it would be slighly more verbose, and it would also require more scanning of information_schema.GLOBAL_STATUS, although I am unsure if that would really matter that much.

What do you think?