mysql设置create_time update_time自动获取时间

DROP TABLE IF EXISTS

comments

; CREATE TABLE

comments

(

id

int(11) NOT NULL AUTO_INCREMENT,

postid

int(11) DEFAULT NULL,

content

varchar(1024) DEFAULT NULL,

fromid

int(11) DEFAULT NULL,

touserid

int(11) DEFAULT NULL,

parentid

int(11) DEFAULT NULL,

create_time

timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,

update_time

timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (

id

) ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4