【mysql】新增列 时间戳
参考地址：https://www.cnblogs.com/SZxiaochun/p/9299392.html
ALTER TABLE worksheet_data_12 ADD COLUMN `input_0` VARCHAR (255), ADD COLUMN `date_112` TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
四种时间戳特性：
TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP TIMESTAMP DEFAULT CURRENT_TIMESTAMP TIMESTAMP ON UPDATE CURRENT_TIMESTAMP TIMESTAMP DEFAULT 'yyyy-mm-dd hh:mm:ss' ON UPDATE CURRENT_TIMESTAMP