postgres=# create database mydb;
CREATE DATABASE
postgres=# alter database mydb;
ALTER DATABASE
postgres=# create table mydbtable(name varchar(80),year int);
CREATE TABLE
postgres=# create table mydbtable(name varchar(80),year int);
ERROR: relation "mydbtable" already exists
postgres=# insert into mydbtable (name,year) values (' xiaoming',23);
INSERT 0 1
postgres=# table mydbtable;
name | year
----------+------
xiaoming | 23
(1 row)
postgres=# select * from mydbtable;
name | year
----------+------
xiaoming | 23
(1 row)
postgres=# select name from mydbtable;
name
----------
xiaoming
(1 row)
postgres=# insert into mydbtable (name,year) values (' xiaohong',23);
INSERT 0 1
postgres=# select name from mydbtable;
name
----------
xiaoming
xiaohong
(2 rows)
postgres=# update mydbtable set name = '< span style="color: #800000;">xiaohei' where name='xiaohong'< /span>;
UPDATE 1
postgres=# select name from mydbtable;
name
----------
xiaoming
xiaohei
(2 rows)
postgres=#
postgres=# delete from mydbtable where name=< span style="color: #800000;">'xiaohei' ;
DELETE 1
postgres=# select name from mydbtable;
name
----------
xiaoming
(1 row)
postgres=# delete from mydbtable;
DELETE 1
postgres=# select * from mydbtable;
name | year
------+------
(0 rows)
postgres=#
postgres=# create database testdb;
CREATE DATABASE
postgres=# alter database testdb;
ALTER DATABASE
postgres=# create database mydb;
CREATE DATABASE
postgres=# alter database mydb;
ALTER DATABASE
postgres=# create table mydbtable(name varchar(80),year int);
CREATE TABLE
postgres=# create table mydbtable(name varchar(80),year int);
ERROR: relation "mydbtable" already exists
postgres=# insert into mydbtable (name,year) values (' xiaoming',23);
INSERT 0 1
postgres=# table mydbtable;
name | year
----------+------
xiaoming | 23
(1 row)
postgres=# select * from mydbtable;
name | year
----------+------
xiaoming | 23
(1 row)
postgres=# select name from mydbtable;
name
----------
xiaoming
(1 row)
postgres=# insert into mydbtable (name,year) values (' xiaohong',23);
INSERT 0 1
postgres=# select name from mydbtable;
name
----------
xiaoming
xiaohong
(2 rows)
postgres=# update mydbtable set name = '< span style="color: #800000;">xiaohei' where name='xiaohong'< /span>;
UPDATE 1
postgres=# select name from mydbtable;
name
----------
xiaoming
xiaohei
(2 rows)
postgres=#
postgres=# delete from mydbtable where name=< span style="color: #800000;">'xiaohei' ;
DELETE 1
postgres=# select name from mydbtable;
name
----------
xiaoming
(1 row)
postgres=# delete from mydbtable;
DELETE 1
postgres=# select * from mydbtable;
name | year
------+------
(0 rows)
postgres=#
postgres=# create database testdb;
CREATE DATABASE
postgres=# alter database testdb;
ALTER DATABASE