mysql建库，建表，补列

Posted 2020-11-04 进击的single

SET NAMES
  UTF8;
DROP DATABASE IF EXISTS
  tmooc;
  CREATE DATABASE tmooc CHARSET=UTF8;
  USE tmooc;
CREATE TABLE stu(
  sid INT PRIMARY KEY AUTO_INCREMENT,
  sname VARCHAR(32) UNIQUE,
  score DOUBLE,
  schoolTime DATE
);
INSERT INTO stu(sname,schoolTime)values("shu",now());
INSERT INTO stu(sname,schoolTime)values("EN",now());
INSERT INTO stu(sname,schoolTime)values("huang",now());
INSERT INTO stu(sname,schoolTime)values("hse",now());
--解决问题，创建表失误，少了一列，下面语句可以补一句
ALTER TABLE stu ADD score DOUBLE(10,2);
--给分数赋初值，不然都会默认为null
UPDATE stu SET score=0;