PostgreSQL

The PostgreSQL cheat sheet provides you with the common PostgreSQL commands and statements.

#Getting started

#Getting started

Switch and connect

$ sudo -u postgres psql

List all databases

postgres=# \l

Connect to the database named postgres

postgres=# \c postgres

Disconnect

postgres=# \q
postgres=# \!

#psql commands

Option Example Description
[-d] <database> psql -d mydb Connecting to database
-U psql -U john mydb Connecting as a specific user
-h -p psql -h localhost -p 5432 mydb Connecting to a host/port
-U -h -p -d psql -U admin -h 192.168.1.5 -p 2506 -d mydb Connect remote PostgreSQL
-W psql -W mydb Force password
-c psql -c '\c postgres' -c '\dt' Execute a SQL query or command
-H psql -c "\l+" -H postgres > database.html Generate HTML report
-l psql -l List all databases
-f psql mydb -f file.sql Execute commands from a file
-V psql -V Print the psql version

#Getting help

- -
\h Help on syntax of SQL commands
\h DELETE DELETE SQL statement syntax
\? List of PostgreSQL command

Run in PostgreSQL console

#Working

#Recon

Show version

SHOW SERVER_VERSION;

Show system status

\conninfo

Show environmental variables

SHOW ALL;

List users

SELECT rolname FROM pg_roles;

Show current user

SELECT current_user;

Show current user's permissions

\du

Show current database

SELECT current_database();

Show all tables in database

\dt

List functions

\df <schema>

#Databases

List databases

\l

Connect to database

\c <database_name>

Show current database

SELECT current_database();

Create database

CREATE DATABASE <database_name> WITH OWNER <username>;

Drop database

DROP DATABASE IF EXISTS <database_name>;

Rename database

ALTER DATABASE <old_name> RENAME TO <new_name>;

#Tables

List tables, in current db

\dt

SELECT table_schema,table_name FROM information_schema.tables ORDER BY table_schema,table_name;

List tables, globally

\dt *.*.

SELECT * FROM pg_catalog.pg_tables

List table schema

\d <table_name>
\d+ <table_name>

SELECT column_name, data_type, character_maximum_length
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = '<table_name>';

Create table

CREATE TABLE <table_name>(
  <column_name> <column_type>,
  <column_name> <column_type>
);

Create table, with an auto-incrementing primary key

CREATE TABLE <table_name> (
  <column_name> SERIAL PRIMARY KEY
);

Delete table

DROP TABLE IF EXISTS <table_name> CASCADE;

#Permissions

Become the postgres user, if you have permission errors

sudo su - postgres
psql

Grant all permissions on database

GRANT ALL PRIVILEGES ON DATABASE <db_name> TO <user_name>;

Grant connection permissions on database

GRANT CONNECT ON DATABASE <db_name> TO <user_name>;

Grant permissions on schema

GRANT USAGE ON SCHEMA public TO <user_name>;

Grant permissions to functions

GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA public TO <user_name>;

Grant permissions to select, update, insert, delete, on a all tables

GRANT SELECT, UPDATE, INSERT ON ALL TABLES IN SCHEMA public TO <user_name>;

Grant permissions, on a table

GRANT SELECT, UPDATE, INSERT ON <table_name> TO <user_name>;

Grant permissions, to select, on a table

GRANT SELECT ON ALL TABLES IN SCHEMA public TO <user_name>;

#Columns

Add column

ALTER TABLE <table_name> IF EXISTS
ADD <column_name> <data_type> [<constraints>];

Update column

ALTER TABLE <table_name> IF EXISTS
ALTER <column_name> TYPE <data_type> [<constraints>];

Delete column

ALTER TABLE <table_name> IF EXISTS
DROP <column_name>;

Update column to be an auto-incrementing primary key

ALTER TABLE <table_name>
ADD COLUMN <column_name> SERIAL PRIMARY KEY;

Insert into a table, with an auto-incrementing primary key

INSERT INTO <table_name>
VALUES (DEFAULT, <value1>);


INSERT INTO <table_name> (<column1_name>,<column2_name>)
VALUES ( <value1>,<value2> );

#Data

[Select](http://www.postgresql.org/docs/current/static/sql-select.html] all data

SELECT * FROM <table_name>;

Read one row of data

SELECT * FROM <table_name> LIMIT 1;

Search for data

SELECT * FROM <table_name> WHERE <column_name> = <value>;

Insert data

INSERT INTO <table_name> VALUES( <value_1>, <value_2> );

Update data

UPDATE <table_name>
SET <column_1> = <value_1>, <column_2> = <value_2>
WHERE <column_1> = <value>;

Delete all data

DELETE FROM <table_name>;

Delete specific data

DELETE FROM <table_name>
WHERE <column_name> = <value>;

#Users

List roles

SELECT rolname FROM pg_roles;

Create user

CREATE USER <user_name> WITH PASSWORD '<password>';

Drop user

DROP USER IF EXISTS <user_name>;

Alter user password

ALTER ROLE <user_name> WITH PASSWORD '<password>';

#Schema

List schemas

\dn

SELECT schema_name FROM information_schema.schemata;

SELECT nspname FROM pg_catalog.pg_namespace;

Create schema

CREATE SCHEMA IF NOT EXISTS <schema_name>;

Drop schema

DROP SCHEMA IF EXISTS <schema_name> CASCADE;

#Commands

#Tables

- -
\d <table> Describe table
\d+ <table> Describe table with details
\dt List tables from current schema
\dt *.* List tables from all schemas
\dt <schema>.* List tables for a schema
\dp List table access privileges
\det[+] List foreign tables

#Query buffer

- -
\e [FILE] Edit the query buffer (or file)
\ef [FUNC] Edit function definition
\p Show the contents
\r Reset (clear) the query buffer
\s [FILE] Display history or save it to file
\w FILE Write query buffer to file

#Informational

- -
\l[+] List all databases
\dn[S+] List schemas
\di[S+] List indexes
\du[+] List roles
\ds[S+] List sequences
\df[antw][S+] List functions
\deu[+] List user mappings
\dv[S+] List views
\dl List large objects
\dT[S+] List data types
\da[S] List aggregates
\db[+] List tablespaces
\dc[S+] List conversions
\dC[+] List casts
\ddp List default privileges
\dd[S] Show object descriptions
\dD[S+] List domains
\des[+] List foreign servers
\dew[+] List foreign-data wrappers
\dF[+] List text search configurations
\dFd[+] List text search dictionaries
\dFp[+] List text search parsers
\dFt[+] List text search templates
\dL[S+] List procedural languages
\do[S] List operators
\dO[S+] List collations
\drds List per-database role settings
\dx[+] List extensions

S: show system objects, +: additional detail

#Connection

- -
\c [DBNAME] Connect to new database
\encoding [ENCODING] Show or set client encoding
\password [USER] Change the password
\conninfo Display information

#Formatting

- -
\a Toggle between unaligned and aligned
\C [STRING] Set table title, or unset if none
\f [STRING] Show or set field separator for unaligned
\H Toggle HTML output mode
\t [on|off] Show only rows
\T [STRING] Set or unset HTML <table> tag attributes
\x [on|off] Toggle expanded output

#Input/Output

- -
\copy ... Import/export table
See also: copy
\echo [STRING] Print string
\i FILE Execute file
\o [FILE] Export all results to file
\qecho [STRING] String to output stream

#Variables

- -
\prompt [TEXT] NAME Set variable
\set [NAME [VALUE]] Set variable (or list all if no parameters)
\unset NAME Delete variable

#Misc

- -
\cd [DIR] Change the directory
\timing [on|off] Toggle timing
\! [COMMAND] Execute in shell
\! ls -l List all in shell

#Large Objects

  • \lo_export LOBOID FILE
  • \lo_import FILE [COMMENT]
  • \lo_list
  • \lo_unlink LOBOID

#Miscellaneous

#Backup

Use pg_dumpall to backup all databases

$ pg_dumpall -U postgres > all.sql

Use pg_dump to backup a database

$ pg_dump -d mydb -f mydb_backup.sql
  •   -a   Dump only the data, not the schema
  •   -s   Dump only the schema, no data
  •   -c   Drop database before recreating
  •   -C   Create database before restoring
  •   -t   Dump the named table(s) only
  •   -F   Format (c: custom, d: directory, t: tar)

Use pg_dump -? to get the full list of options

#Restore

Restore a database with psql

$ psql -U user mydb < mydb_backup.sql

Restore a database with pg_restore

$ pg_restore -d mydb mydb_backup.sql -c
  •   -U   Specify a database user
  •   -c   Drop database before recreating
  •   -C   Create database before restoring
  •   -e   Exit if an error has encountered
  •   -F   Format (c: custom, d: directory, t: tar, p: plain text sql(default))

Use pg_restore -? to get the full list of options

#Remote access

Get location of postgresql.conf

$ psql -U postgres -c 'SHOW config_file'

Append to postgresql.conf

listen_addresses = '*'

Append to pg_hba.conf (Same location as postgresql.conf)

host  all  all  0.0.0.0/0  md5
host  all  all  ::/0       md5

Restart PostgreSQL server

$ sudo systemctl resatart postgresql

#Import/Export CSV

Export table into CSV file

\copy table TO '<path>' CSV
\copy table(col1,col1) TO '<path>' CSV
\copy (SELECT...) TO '<path>' CSV

Import CSV file into table

\copy table FROM '<path>' CSV
\copy table(col1,col1) FROM '<path>' CSV

See also: Copy

#See Also