use the db-merger that ships with anope...
2) Anope Database Merger
This program tries to merge two standard Anope database sets (ChanServ,
NickServ, BotServ, and MemoServ).
To merge two database sets, put them both in the folder where the merger
is located. The first database set must be named <name>1.db (nick1.db,
chan1.db, etc); the second database set must be named <name>2.db (nick2.db,
chan2.db, etc). If you execute the merger now the databases will be merged
into databases named <name>.db.
Credits:
Written by Florian Schulze <certus@anope.org>