数据库的创建与模糊查询

数据库名称可以为【schoolDB】，字符集【utf8】，排列规则【utf8_general_ci】。

创建表

CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '学号',
  `createDate` datetime DEFAULT NULL,
  `userName` varchar(20) DEFAULT NULL,
  `pwd` varchar(36) DEFAULT NULL,
  `phone` varchar(11) DEFAULT NULL,
  `age` tinyint(3) DEFAULT NULL,
  `sex` char(2) DEFAULT NULL,
  `introduce` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;

插入数据

insert into student values(0,'2024-02-21 10:10:10','赵灵儿','123',
'15612345678',16,'女','逍遥哥哥，你终于找到我了');
insert into student values(0,'2024-02-25 10:10:10','王语嫣','123',
'15612345678',17,'女','慕容复,我和你不共戴天。');
insert into student values(0,'2024-02-22 10:10:10','龙姑娘','123',
'15612345678',22,'女','我想过过过儿过过的日子。');
insert into student values(0,'2024-02-14 10:10:10','杨过','123',
'15612345678',18,'男','一遇杨过误终身。');
insert into student values(0,'2024-02-25 10:10:10','杨逍遥','123',
'15612345678',27,'男','杨过和程英的大儿子。');
insert into student(userName,age,introduce) values('黄衣女子',26,
'杨过与龙姑娘的大女儿。');

模糊查询语句

#like的使用语法，where后 先写查询列再写like,最后写匹配字符串
SELECT * FROM student where userName like '杨_';
SELECT * FROM student where userName like '杨%';
SELECT * FROM student where introduce like '%大%';
#模糊查询基本上所有后台管理系统都会有此功能

select * from student where pwd is not null;
#范围查询·between and是包含==的,既可以查询数值范围，也可以查询时间范围，用途广泛。
select * from student where age between 22 and 30;
select * from student where createDate BETWEEN '2024-02-21 00:00:00' and '2024-02-25 00:00:00';

#in关键字的使用·不建议使用这个关键字，因为它不一定走索引，在百万表的数据中会很卡。
select * from student where userName in ('赵灵儿','杨过','龙姑娘');