常用sql命令
insert into user_info(name, signup_date, email) values(‘黄剑’, ‘2017-03-01’, ‘1342042894@qq.com’); delete from user_info where name = ‘李四’; select * from user_info; update user_info set name=’李四’ where name=’张三’;
alter table user_tbl rename to user_info; alter table user_info add email varchar(40); alter table user_info alter column signup_date set not null;
alter table user_info add id int; alter table user_info drop column id;
ALTER TABLE public.user_info ADD COLUMN id integer; ALTER TABLE public.user_info ALTER COLUMN id SET NOT NULL; ALTER TABLE public.user_info ALTER COLUMN id SET DEFAULT nextval(‘user_info_id_seq’::regclass);
create table t_tb(id serial, phone varchar(200)); drop table if exists t_tb;
安装
sudo apt-get update
sudo apt-get install postgresql
Creating new cluster 9.5/main … config /etc/postgresql/9.5/main data /var/lib/postgresql/9.5/main locale en_US.UTF-8 socket /var/run/postgresql port 5432
配置数据库以允许远程连接访问。
安装完成后,默认只能本地才能连接数据库,其他机子访问不了,需要进行配置。
修改监听地址 sudo gedit /etc/postgresql/9.5/main/postgresql.conf 将 #listen_addresses = ‘localhost’ 的注释去掉并改为 listen_addresses = ‘*’
修改可访问用户的IP段 sudo gedit /etc/postgresql/9.5/main/pg_hba.conf 在文件末尾添加: host all all 0.0.0.0 0.0.0.0 md5 ,表示运行任何IP连接
重启数据库 sudo /etc/init.d/postgresql restart
添加新用户和新数据库
法一:使用PostgreSQL客户端psql 运行系统用户”postgres”的psql命令,进入客户端:
sudo -u postgres psql 创建用户”xiaozhang”并设置密码:
postgres=# create user xiaozhang with password ‘123456’; 创建数据库exampledb,所有者为xiaozhang:
postgres=# create database exampledb owner xiaozhang; 将exampledb数据库的所有权限赋予xiaozhang,否则xiaozhang只能登录psql,没有任何数据库操作权限:
grant all privileges on database exampledb to xiaozhang;
sudo -u postgres psql
psql -U dbuser -d exampledb -h 127.0.0.1 -p 5432
\l:列出所有数据库。 \d:列出当前数据库的所有表格。 \d [table_name]:列出某一张表格的结构。
\password:设置密码 \q:退出 \h:查看SQL命令的解释,比如\h select。 \?:查看psql命令列表。 \c [database_name]:连接其他数据库。 \du:列出所有用户。 \e:打开文本编辑器。 \conninfo:列出当前数据库和连接的信息。
http://www.cnblogs.com/z-sm/archive/2016/07/05/5644165.html
select * from dbusers
select * from dbusers where name=’dnxdev | zxcvzxcv2015@163.com’ |
select id from dbusers where name=’dnxdev | zxcvzxcv2015@163.com’ |
select * from vlns
select * from vlns where no_delete=1 and dbuser_id=(select id from dbusers where name=’dnxdev | zxcvzxcv2015@163.com’) |
select id from vlns where no_delete=1 and dbuser_id=(select id from dbusers where name=’dnxdev | zxcvzxcv2015@163.com’) |
-- Table: public."Persons"
-- DROP TABLE public."Persons";
CREATE TABLE public."Persons"
(
id integer NOT NULL DEFAULT nextval('"Persons_id_seq"'::regclass),
"LastName" character varying,
"FirstName" character varying,
"Address" character varying,
"City" character varying,
CONSTRAINT "Persons_pkey" PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE public."Persons"
OWNER TO huangjian;
select * from "Persons";
清空数据表
truncate table "Persons";
insert into "Persons"("LastName", "FirstName", "Address", "City")
values('Adams', 'John', 'Oxford Street', 'London');
insert into "Persons"("LastName", "FirstName", "Address", "City")
values('Bush', 'George', 'Fifth Avenue', 'New York');
insert into "Persons"("LastName", "FirstName", "Address", "City")
values('Carte', 'Thomas', 'Changan Street', 'Beijing');
select "City" from "Persons";
select distinct "City" from "Persons"; 相同的只出现一次
select * from "Persons" where "City"='Beijing';