PostgreSQL common statement

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