Chang your SQL query to read:
in reply to using fetchrow_hashref
and then use 'foobar' in the hash ref.
SELECT code, sum(number) as foobar FROM $serverTabl_4 group by code
Basically, the keys are whatever it thinks the column name is..so if you use 'sum(column)', 'avg(column)' or the like, it names the key that. If you tack on the 'as something_else' after it, you can effectively name the keys whatever you like. This is also handy when you have a join across two tables that have similarily named columns :)
Update: Heh. 3rd fastest keys in the west...