【mysql】mysql 經常使用建表語句

引用：http://blog.csdn.net/kakane/article/details/7401111

【1】創建員工檔案表
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】合理選擇數據類型及字段修飾符，要求有NOT NULL，auto_increment, primary key等。

--
-- make by kakane
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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】查看錶的結構

mysql> desc  workers_info;

 

【4】新增qq和tel字段，要求tel字段位於email前，要求入職時間是最後一個字段

 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字段修改爲mailbox
 mysql> ALTER TABLE workers_info CHANGE email mailbox varchar(30);

【6】向表裏添加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】查詢入職時間在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

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】統計男員工人數、女員工人數

mysql> select count(男) from workers_info where sex="M";
mysql> select count(男) from workers_info where sex="M";

【14】按照入職時間前後進行排序，並顯示前5位員工姓名

mysql> select * from workers_info ORDER BY EmployedDates limit 5;