PostgreSQL 常用语句

postgres=# create database mydb;
CREATE DATABASE

postgres=# alter database mydb;
ALTER DATABASE

postgres=# create table mydbtable(name varchar(),year int);
CREATE TABLE

postgres=# create table mydbtable(name varchar(),year int);
ERROR:  relation "mydbtable" already exists

postgres=# insert into mydbtable (name,year) values ('xiaoming',);
INSERT  

postgres=# table mydbtable;
   name   | year
----------+------
 xiaoming |
( row)

postgres=# select * from mydbtable;
   name   | year
----------+------
 xiaoming |
( row)

postgres=# select name from mydbtable;
   name
----------
 xiaoming
( row)

postgres=# insert into mydbtable (name,year) values ('xiaohong',);
INSERT
postgres=# select name from mydbtable;
   name
----------
 xiaoming
 xiaohong
( rows)

postgres=# update mydbtable set name = 'xiaohei' where name='xiaohong';
UPDATE
postgres=# select name from mydbtable;
   name
----------
 xiaoming
 xiaohei
( rows)
postgres=# 

postgres=# delete from mydbtable where name='xiaohei';
DELETE
postgres=# select name from mydbtable;
   name
----------
 xiaoming
( row)

postgres=# delete from mydbtable;
DELETE
postgres=# select * from mydbtable;
 name | year
------+------
( rows)
postgres=# 

postgres=# create database testdb;
CREATE DATABASE

postgres=# alter database testdb;
ALTER DATABASE