Truncate table语句用来删除/截断表里的所有数据

• 和delete删除所有表数据在逻辑上含义相同，但性能更快
• 类似执行了drop table和create table两个语句

执行代码

mysql> select * from students_bak;+-----+----------+--------+---------+| sid | sname | gender | dept_id |+-----+----------+--------+---------+| 101 | zhangsan | male | 10 || 1 | aa | 1 | 1 |+-----+----------+--------+---------+2 rows in set (0.00 sec)mysql> truncate table students_bak;Query OK, 0 rows affected (0.16 sec)mysql> select * from students_bak;Empty set (0.00 sec)mysql> set autocommit=off;Query OK, 0 rows affected (0.01 sec)mysql> select * from students3;+-----+-------+--------+---------+--------+| sid | sname | gender | dept_id | sname2 |+-----+-------+--------+---------+--------+| 100 | NULL | 1 | 1 | NULL |+-----+-------+--------+---------+--------+1 row in set (0.01 sec)mysql> truncate table students3;Query OK, 0 rows affected (0.06 sec)mysql> rollback;Query OK, 0 rows affected (0.00 sec)mysql> select * from students3;Empty set (0.00 sec)mysql> delete from students;Query OK, 5 rows affected (0.00 sec)mysql> select * from students;Empty set (0.00 sec)mysql> rollback;Query OK, 0 rows affected (0.07 sec)mysql> select * from students;+-----+-------+--------+---------+| sid | sname | gender | dept_id |+-----+-------+--------+---------+| 1 | aa | 3 | 1 || 4 | cc | 3 | 1 || 5 | dd | 1 | 2 || 6 | aac | 1 | 1 || 10 | a | 1 | 1 |+-----+-------+--------+---------+5 rows in set (0.00 sec)

truncate需要什么权限

truncate的执行是先drop后create的， 所以truncate包含drop和create，是一个复合的动作， 对于create不用赋予， 所以只需要赋予drop权限就可以了

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