Aggregate function optimization for same column in same record

[Nathan Alden]

If I perform an aggregate function on a particular column more than once per record in a grouped result set, is the aggregate function processed separately each time or does MySQL recognize that the result of the function should be the same in each case?

My actual SQL is more complicated than the following, but it does demonstrate the question:

select sum(column1), sum(column1)
from table1

Is sum() actually calculated twice or does MySQL realize the value should be the same and used a "cached" value instead for subsequent calls?

Thanks all.