SQL日常练习

1.建表语句----DDL

CREATE TABLE `月光` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `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 '男',
  `introduce` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;

2.插入语句----SQL

INSERT into 月光 VALUES(0,'2024-02-18 00:00:00','江若琳','1314520','15931055753',19,'女','宇宙无敌超级美女')
INSERT into 月光 VALUES(1,'2024-03-25 00:00:00','高乙磊','1314521','15931055756',19,'男','查无此人')

3.基础查询语句---DQL

SELECT * FROM  月光;
SELECT username as '姓名',age,sex,'性别',introduce'简介'
FROM 月光
where pwd is not null;
SELECT DISTINCT sex '性别类型' FROM 月光;
SELECT username as '姓名',age,sex,'性别',introduce'简介' FROM 月光 ORDER BY age desc;
SELECT *from 月光 LIMIT 2