Drops all tables, views and routines in database. Based on http://stackoverflow.com/a/18625545/2512304

DropAllTables

SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;

-- drop tables

SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_name, '`') INTO @tables
  FROM information_schema.tables
  WHERE table_schema = (SELECT DATABASE()); -- from currently selected schema
SELECT IFNULL(@tables, 'dummy') INTO @tables; -- to prevent error when there are already no tables
 
SET @tables = CONCAT('DROP TABLE IF EXISTS ', @tables);
PREPARE stmt FROM @tables;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- drop views

SET @views = NULL;
SELECT GROUP_CONCAT('`', table_name, '`') INTO @views
  FROM information_schema.views
  WHERE table_schema = (SELECT DATABASE());
SELECT IFNULL(@views, 'dummy') INTO @views;
 
SET @views = CONCAT('DROP VIEW IF EXISTS ', @views);
PREPARE stmt FROM @views;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- drop routines (functions and procedures)

DELETE FROM mysql.proc WHERE db = (SELECT DATABASE()) AND (type = 'PROCEDURE' OR type = 'FUNCTION');

SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;