Sometimes it can be useful to completely drop all tables in a database, for example to reset a DB to a previous version from a backup.
After checking that you are doing this on the right database and that you know what you are doing, you can do this:
SET FOREIGN_KEY_CHECKS = 0;
SET GROUP_CONCAT_MAX_LEN=32768;
SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_name, '`') INTO @tables
FROM information_schema.tables
WHERE table_schema = (SELECT DATABASE());
SELECT IFNULL(@tables,'dummy') INTO @tables;
SET @tables = CONCAT('DROP TABLE IF EXISTS ', @tables);
PREPARE stmt FROM @tables;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET FOREIGN_KEY_CHECKS = 1;
All credits goes to this guy on Stackoverflow.