数据库常用命令（增删改查等）

--建表
CREATE TABLE student (
  stu_id NUMBER(10) NOT NULL PRIMARY KEY,
  stu_name VARCHAR(20)  DEFAULT NULL,
  stu_id_card VARCHAR(18)  DEFAULT NULL,
  stu_pwd VARCHAR(32)  DEFAULT NULL,
  stu_mobile VARCHAR(11)  DEFAULT NULL,
  stu_gender NUMBER(1) DEFAULT NULL,
  enrollment_date DATE DEFAULT NULL,
  remark VARCHAR(200) DEFAULT NULL,
  del_mark NUMBER(1) DEFAULT 1
);

--增加数据
INSERT INTO student(stu_id,stu_name,stu_id_card,stu_pwd,stu_mobile,stu_gender,enrollment_date,remark,del_mark)  
VALUES (1,'小明','610123200210202345','pwd123','13500001111',1,to_date('2025-02-09','yyyy-mm-dd'),'stu测试',1);

--删除数据
DELETE FROM student WHERE stu_id = 1;

--修改数据
UPDATE student SET stu_name = '蔡坤坤' WHERE stu_id = 1 AND stu_name = '小明';

--查询数据
SELECT * FROM student;

查询前几条数据，并按修改时间降序排列

SELECT 5 * FROM student ORDER BY Update_Time