mysql 使用表 语句_【mysql】mysql 经常使用建表语句
【1】創(chuàng)建員工檔案表
要求字段:員工員工編號,員工姓名,性別,工資,email,入職時間,部門。
【2】合理選擇數(shù)據(jù)類型及字段修飾符,要求有NOT NULL,auto_increment, primary key等。
--
-- make by kakane
--
DROP TABLE IF EXISTS `workers_info`;
CREATE TABLE `workers_info` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`workername` varchar(20) NOT NULL,
`sex` enum(F,M,S),
`salary` int(11) DEFAULT '0',
`email` varchar(30),
`EmployedDates` date,
`department` varchar(30),
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
mysql> alter table workers_info ADD sex enum('F','M','S');
【3】查看表的結(jié)構(gòu)html
mysql> desc workers_info;
【4】新增qq和tel字段,要求tel字段位于email前,要求入職時間是最后一個字段mysql
mysql> ALTER TABLE workers_info ADD tel varchar(15) after salary;
mysql> ALTER TABLE workers_info ADD qq int;
ALTER TABLE workers_info MODIFY EmployedDates date after qq;
【5】把email字段修改為mailbox
mysql> ALTER TABLE workers_info CHANGE email mailbox varchar(30);
【6】向表里添加10條記錄
mysql> INSERT INTO workers_info values(NULL,'xing',10000,'1598232123','xing@qq.com','yanfa',736019646,20121221);
mysql> INSERT INTO workers_info (workername,salary,tel,mailbox,department,qq,EmployedDates) values('xing',10000,'1598232123','xing@qq.com','yanfa',736019646,20121221);
【7】修改其中兩條記錄的tel和mailbox
mysql> UPDATE workers_info SET mailbox = 'haha@qq.com' WHERE id = 14;
mysql> UPDATE workers_info SET mailbox = 'haha@qq.com',tel='1246543423' WHERE id = 13;
【8】查看所添加記錄
mysql> select * from workers_info;
【9】查看姓名和入職時間記錄
mysql> select workername,EmployedDates from workers_info;
【10】查詢?nèi)肼殨r間在2003年之前的
mysql> select * from workers_info where year(EmployedDates) < 2003;
【11】查詢工資最高和最低的員工姓名sql
mysql> select * from workers_info ORDER BY salary limit 1;
mysql> select * from workers_info ORDER BY salary desc limit 1;
【12】查詢平均工資
mysql> select avg(salary) from workers_info;
【13】統(tǒng)計男員工人數(shù)、女員工人數(shù)spa
mysql> select count(男) from workers_info where sex="M";
mysql> select count(男) from workers_info where sex="M";
【14】按照入職時間前后進(jìn)行排序,并顯示前5位員工姓名
mysql> select * from workers_info ORDER BY EmployedDates limit 5;
總結(jié)
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