I’m not exactly sure what you are looking for but it sounds like you are looking for call detail records. Asterisk writes CDR records by default to /var/log/asterisk/cdr-csv/Master.csv. This will tell you number of calls, call lengths, and other general things used for billing.
Also of note, you can configure asterisk to write CDR’s to database. Which will probably be more convenient for ‘real-time’ access.
I know that you can use just about any database that you want either through ODBC or a direct module. Most notable are MySQL and Postgre SQL. There may also be an Oracle one but I don’t know. MySQL is compiled in through the asterisk-addons packages, while Postgre SQL and ODBC are compiled in through the default build of Asterisk ( assuming you have the required development files on your computers ).