mysql5.1中delete和truncate的区别，实例如下

create table test_del(id int auto_increment,name varchar(10),primary key(id));
insert into test_del(name) values('xuhao'),('fdsa'),('fddsf');
create table test_truc(id int auto_increment,name varchar(10),primary key(id));
insert into test_truc(name) values('xuhao'),('fdsa'),('fddsf');

mysql> select * from test_del;
+----+-------+
| id | name  |
+----+-------+
|  1 | xuhao |
|  2 | fdsa  |
|  3 | fddsf |
+----+-------+
3 rows in set

mysql>  select * from test_truc;
+----+-------+
| id | name  |
+----+-------+
|  1 | xuhao |
|  2 | fdsa  |
|  3 | fddsf |
+----+-------+
3 rows in set

mysql> delete from test_del;
Query OK, 3 rows affected

mysql> delete from test_truc where true;
Query OK, 3 rows affected

mysql> insert into test_del(name) values('xuhao'),('fdsa'),('fddsf');
Query OK, 3 rows affected
Records: 3  Duplicates: 0  Warnings: 0

mysql> insert into test_truc(name) values('xuhao'),('fdsa'),('fddsf');
Query OK, 3 rows affected
Records: 3  Duplicates: 0  Warnings: 0

mysql>  select * from test_del;
+----+-------+
| id | name  |
+----+-------+
|  4 | xuhao |
|  5 | fdsa  |
|  6 | fddsf |
+----+-------+
3 rows in set

mysql>  select * from test_truc;
+----+-------+
| id | name  |
+----+-------+
|  4 | xuhao |
|  5 | fdsa  |
|  6 | fddsf |
+----+-------+
3 rows in set

mysql> truncate test_truc;
Query OK, 0 rows affected

mysql> insert into test_truc(name) values('xuhao'),('fdsa'),('fddsf');
Query OK, 3 rows affected
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from test_truc;
+----+-------+
| id | name  |
+----+-------+
|  1 | xuhao |
|  2 | fdsa  |
|  3 | fddsf |
+----+-------+
3 rows in set

对于表中的自增id，delete和truncate的处理方式是不同，另外据说delete操作会写入日志，truncate不写入日志，言下之意，truncate慎用，不易恢复。