MySQL 错误 "There can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause"即使我没有做错

Question

CREATE TABLE AlarmHistory
(
    id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    value DOUBLE NOT NULL,
    startedStamp TIMESTAMP NOT NULL,
    finishedStamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
);

尝试创建上表时出现以下错误:“SQL 错误 (1293):表定义不正确；在 DEFAULT 或 ON UPDATE 子句中只能有一个带有 CURRENT_TIMESTAMP 的 TIMESTAMP 列”。

我的问题是这是一个错误吗？因为当然，我有两个 TIMESTAMP 列，但其中只有一个具有默认定义。当我删除 startedStamp 时，我没有错误。

Answer 1

根据 MySQL 手册，版本 5.5，Automatic Initialization and Updating for TIMESTAMP

With neither DEFAULT CURRENT_TIMESTAMP nor ON UPDATE CURRENT_TIMESTAMP, it is the same as specifying both DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP.

CREATE TABLE t1 (
  ts TIMESTAMP
);

但是，

With a constant, the default is the given value. In this case, the column has no automatic properties at all.

CREATE TABLE t1 (
  ts TIMESTAMP DEFAULT 0
);

所以，这应该可行:

CREATE TABLE AlarmHistory
(
    id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    value DOUBLE NOT NULL,
    startedStamp TIMESTAMP DEFAULT 0 NOT NULL,
    finishedStamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL
);

fiddle