MySQL Delete all rows from table and reset ID to zero

Question

I need to delete all rows from a table but when I add a new row, I want the primary key ID, which has an auto increment, to start again from 0 respectively from 1.

Answer 1

If table has foreign keys then I always use following code:

SET FOREIGN_KEY_CHECKS = 0; -- disable a foreign keys check
SET AUTOCOMMIT = 0; -- disable autocommit
START TRANSACTION; -- begin transaction

/*
DELETE FROM table_name;
ALTER TABLE table_name AUTO_INCREMENT = 1;
-- or
TRUNCATE table_name;
-- or
DROP TABLE table_name;
CREATE TABLE table_name ( ... );
*/

SET FOREIGN_KEY_CHECKS = 1; -- enable a foreign keys check
COMMIT;  -- make a commit
SET AUTOCOMMIT = 1 ;

But difference will be in execution time. Look at above Sorin's answer.