【PostgresQL】PostgresQL 基本操作

1、登陸PostgresQL

psql -U postgres -d postgres

2、創建表users

create table users(
id serial,
name varchar(20)
);

3、增加字段

alter table users add column age int;

4、修改字段類型

alter table users alter column age type varchar(10);

5、修改字段名稱

alter table users rename age to school;

6、刪除字段

alter table users drop column school;

7、刪掉字段兩邊的空格

update users set name = btrim(name);

8、刪除重複數據

alter table users add column score int;
insert into users values(1, 'zhenqing.wang1', 99);
insert into users values(2, 'zhenqing.wang2', 97);
insert into users values(3, 'zhenqing.wang3', 99);
select ctid, * from users where ctid not in (select max(ctid) from users group by score);
delete from users where ctid not in (select max(ctid) from users group by score);

9、導入導出數據

本地導入數據
psql -U postgres -d postgres < /home/zhenqingwang/Desktop/1.sql
本地導出數據
pg_dump -U postgres -d postgres > /home/zhenqingwang/Desktop/1.sql