sqlmap - Dump multiple columns at once?

I'm playing around with sqlmap, and I'm having a little trouble dumping database columns.

I can dump all of them at once which is great, but this database has thousands of users and dumping every column would take over a day, whereas dumping columns individually only takes about 15 minutes. The only problem with this is that all the data is dumped from A-Z, which means I have no idea which hash is for which user.

Is there a way of dumping multiple columns (but not all) at once to prevent them being mixed up?

Cheers!