Hello,
I can offer you our software Caligare Flow Inspector (http://www.caligare.com). It is a pure NetFlow analyzer,
which met all your requirements. Flows are stored in SQL tables in easy format, so can run all your queries
directly in SQL. Table format is [h|d|w|m][collector_id]_[YYMM[DD[HH]] where h,d,w and m means hourly,
daily, weekly or monthly table. Collector ID is a unique collector identification and the rest is a time format.
See http://www.caligare.com/download/netflow.pdf and appendix section about table fields name, etc ....
Please, feel free to contact me directly on my email nejman (at) caligare (dot) com.
In any case you can use competitors software i.e. Fluke or ManageEngine. Both are using MySQL
for data storage. I have a little knowledge of cisco's NFC, but I know all product mentioned above.
Have a nice day,
Jan Nejman
Caligare, co.
http://www.caligare.com/