I have SQLite databases named database1 with a table t1 and database2 with a table t2. I want to import table t2
Open database2 with the sqlite3 command-line tool and read the table definition with the command .schema t2.
(Alternatively, use any other tool that allows to read the table definition.)
Then open database1, attach the other database with the command:
ATTACH 'database2file' AS db2;
then create the table t2, and copy the data over with:
INSERT INTO t2 SELECT * FROM db2.t2;