Question

I want to keep t1,t2 and drop all other tables.

Answer 1

You can use information_schema to find table names, and even format the results as a bunch of DROP statements.

SELECT CONCAT('DROP TABLE ', TABLE_NAME, '; ')
  FROM information_schema.tables
  WHERE table_schema = DATABASE() AND table_name NOT IN ('foo', 'bar', 'baz');

(The DATABASE() function returns the currently use‘d database.)

Using PREPARE and EXECUTE, you could even avoid copy & paste, and (in MySQL 5.0.13 and later) write a stored procedure to do this.