一、TIMESTAMP 的字段设置为 NULL 等价于设置为当前时间
UPDATE test_table s SET s.audit_time = NULL, s.update_time = now() WHERE s.user_id = 3
等价于
UPDATE test_table s SET s.audit_time = now(), s.update_time = now() WHERE s.user_id = 3
一、TIMESTAMP 的字段设置为 NULL 等价于设置为当前时间
UPDATE test_table s SET s.audit_time = NULL, s.update_time = now() WHERE s.user_id = 3
等价于
UPDATE test_table s SET s.audit_time = now(), s.update_time = now() WHERE s.user_id = 3