一、增加语句
insert into 表名 values(列的值);
往表里插入数据 into可省略
DROP TABLE IF EXISTS student;
CREATE TABLE student (
id INT,
sn INT comment '学号',
name VARCHAR(20) comment '名称',
qq_mail VARCHAR(10) comment 'QQ邮箱'
);
- 单行 + 全列插入
INSERT INTO student VALUES (1,100,'章三',null);
INSERT INTO student VALUES (2,200,'李斯',20385521);
- 多行 + 指定列插入
INSERT INTO student (id,sn,name) VALUES
(102,9527,'终极宇宙真理'),
(150,5829,'终极次元真理');
二、查询语句
查询语句是所有语句中最重要的!
创建了一张名字叫Flsh的表
create table grade (
id int,
Name varchar(10),
yuwen decimal(3,1),
shuxue decimal(3.1),
yingyu decimal(3.1)
);
创建一张成绩单
INSERT INTO grade (id,`name`,yuwen,shuxue,yingyu) VALUES
(1,'李元霸',50,55.5,62),
(2,'宇文成都',99,60.5,92),
(3,'李存孝',99,80.5,72),
(4,'李孝恭',99,55,99),
(5,'李成',25,25.5,32);
查找分数yingyu低于60
SELECT `name`, yingyu FROM grade WHERE yingyu <60 ;
查询yuwen大于yingyu的成绩
SELECT name, yuwen, yingyu FROM grade WHERE yuwen > yingyu;
查看3门成绩综合小于150
SELECT name, yuwen + shuxue + yingyu 总分 FROM grade
WHERE yuwen + shuxue + yingyu < 150;