INSERT INTO database1.table1 SELECT * FROM database2.table2;

USE database1;
SELECT * INTO OUTFILE  "tabledump.txt"  FROM table1;
USE database2;
LOAD DATA INFILE  "tabledump.txt"  INTO TABLE my_table;

 -- Note that these rules mean a file given as `./myfile.txt%af_src_str_0s
 
 -- data directory, whereas a file given as `myfile.txt%af_src_str_1 from the database directory for db1 because
 
 -- db1 is the current database, even though the statement explicitly loads the file
 
-- into a table in the db2 database:

select a.fld1, b.fld2 from db1.tbl1 a, db2.tbl2 b