Mysql常用語句部分(1)
阿新 • • 發佈：2019-01-28
create database oa;//建立資料庫
drop database oa;//刪除資料庫
use oa;//使用資料庫
alter table zhulei add column createTime timestamp default CURRENT_TIMESTAMP; //給表新增屬性
alter table person modify id int AUTO_INCREMENT;//修改表屬性 新增自動增長列
alter table person modify name varchar(40) UNIQUE ;//新增唯一屬性
insert into person(name,sex) values('zhulei','男');//插入資料
update person set sex='女'//更新所有資料
alter table person modify sex enum('男','女');//新增列舉型別
alter table person add age int after sex;//在sex之後新增屬性 之前first
create table users(
id int primary key,
username varchar(20) not null,
userpass varchar(20) not null,
preson_id int foreign key (person_id) REFERENCES person(id)); //建立時新增外來鍵屬性
create table users_temp(
id int primary key,
username varchar(20) not null,
userpass varchar(20) not null,
createTime TIMESTAMP default CURRENT_TIMESTAMP,
person_id int ,
KEY `person` (`person_id`),
CONSTRAINT `person` FOREIGN KEY (`person_id`) REFERENCES `person` (`id`));
create table users_temp(
id int primary key,
username varchar(20) not null,
userpass varchar(20) not null,
createTime TIMESTAMP default CURRENT_TIMESTAMP,
person_id int ,
index `person` (`person_id`),
CONSTRAINT `person` FOREIGN KEY (`person_id`) REFERENCES `person` (`id`));//注意索引必須不能相同
select * from person p join users u on u.person_id=p.id;//連線查詢
select * from person p left join users u on u.person_id=p.id;//左連線
select * from person p right join users u on u.person_id=p.id;//右連線
show create table users; //顯示建立的語句
DROP TABLE IF EXISTS `dept`;//刪除表中資料
create table dept(
deptNo varchar(40) primary key ,
name varchar(40) not null,
createDeptTimes timestamp,
managerNo varchar(40),
PRIMARY KEY (deptNo),
index manager (managerNo),
CONSTRAINT manager FOREIGN KEY (managerNo) REFERENCES emp (empNo));