MySQL truncate table语句的使用

May ·

更新时间:2024-11-15

· 626 次阅读

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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TRUNCATE table Mysql

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