使用 SQLITE - Attach 這個指令即可：

$ ls
a.sqlite3 b.sqlite3
$ sqlite3
sqlite> attach 'a.sqlite3' as adb
sqlite> attach 'b.sqlite3' as bdb
sqlite> .tables
adb.user  bdb.data
sqlite> SELECT adb.user.id, adb.user.name, bdb.data.info FROM adb.user, bdb.data WHERE adb.user.id = bdb.data.id