【PostgresQL】PostgresQL 基本操作

1、登陆Postgresql

psql -U postgres -d postgres

2、创建表users

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

3、增加字段

alter table users add column age int;

4、修改字段类型

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

5、修改字段名称

alter table users rename age to school;

6、删除字段

alter table users drop column school;

7、删掉字段两边的空格

update users set name = btrim(name);

8、删除重复数据

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、导入导出数据

本地导入数据
psql -U postgres -d postgres < /home/zhenqingwang/Desktop/1.sql
本地导出数据
pg_dump -U postgres -d postgres > /home/zhenqingwang/Desktop/1.sql