MySQL - TIMESTAMP的默认值(3)

Question

我的数据库是MySql 5.6.

我想使用CURRENT_TIMESTAMP作为默认值,属性类型为TIMESTAMP(3).

但我得到错误:

错误1067(42000):"已更新"的默认值无效

我认为这是因为CURRENT_TIMESTAMP只有第二精度.

如何将当前时间设置为timestamp带小数部分的默认值？

Answer 1

根据文档timestamp和datetime类型列:

如果a TIMESTAMP或DATETIME列定义在任何地方包含显式小数秒精度值,则必须在整个列定义中使用相同的值.

这是允许的:

CREATE TABLE t1 (
  ts TIMESTAMP(6) DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6)
);

其他例子:

mysql> create table tbl_so_q23671222_1( ts timestamp(3) default now() );
ERROR 1067 (42000): Invalid default value for 'ts'

mysql> create table tbl_so_q23671222_1( ts timestamp(3) default now(3) );
Query OK, 0 rows affected (0.59 sec)

mysql> create table tbl_so_q23671222_2( ts timestamp(3) default current_timestamp );
ERROR 1067 (42000): Invalid default value for 'ts'

mysql> create table tbl_so_q23671222_2( ts timestamp(3) default current_timestamp(3) );
Query OK, 0 rows affected (0.38 sec)

mysql> desc tbl_so_q23671222_1;
+-------+--------------+------+-----+----------------------+-------+
| Field | Type         | Null | Key | Default              | Extra |
+-------+--------------+------+-----+----------------------+-------+
| ts    | timestamp(3) | NO   |     | CURRENT_TIMESTAMP(3) |       |
+-------+--------------+------+-----+----------------------+-------+
1 row in set (0.01 sec)

mysql> desc tbl_so_q23671222_2;
+-------+--------------+------+-----+----------------------+-------+
| Field | Type         | Null | Key | Default              | Extra |
+-------+--------------+------+-----+----------------------+-------+
| ts    | timestamp(3) | NO   |     | CURRENT_TIMESTAMP(3) |       |
+-------+--------------+------+-----+----------------------+-------+
1 row in set (0.01 sec)

请参阅:
TIMESTAMP和DATETIME的初始化和更新