mysql> create table test (
-> id int primary key not null auto_increment,
-> username varchar(15) not null
-> );
mysql> insert into test (username) values ('cloudchen');
mysql> insert into test (username) values ('mumac');
mysql> insert into test (username) values ('jordan');
mysql> insert into test (username) values ('michael');
mysql> insert into test (username) values ('michael');
mysql> insert into test (username) values ('michael');
mysql> insert into test (username) values ('michael');
mysql> insert into test (username) values ('michael');
mysql> delete from test where username = 'michael' order by id desc limit 2;