A quick reference to PostgreSQL.

Created on: 2019-01-22

Tag: cheat_sheet

PostgreSQL CHEAT SHEET DROP VIEW viewname; Delete a view DROP INDEX idxname; Drop an index CREATE VIEW v(c1,c2) AS SELECT c1, c2 FROM t; WITH CASCADED LOCAL CHECK OPTION; Create a new view with check option CREATE RECURSIVE VIEW v AS select-statement -anchor part UNION ALL select-statement; -recursive part. Show my ip and location.

  • Importing Data from CSV in PostgreSQL Insert multiple rows List the tables in SQLite opened with ATTACH Meta commands in PSQL Outputting Query Results to Files with o Random Sequences Show Tables in Postgres SQL Cheat Sheet.
  • PostgreSQL Cheat Sheet The PostgreSQL cheat sheet provides you with the common PostgreSQL commands and statements that enable you to work with PostgreSQL quickly and effectively. Download PostgreSQL cheat sheet We provide you with a 3-page PostgreSQL cheat sheet in PDF format.
  • Quit from psql q -version select version; -Create PostgreSQL database create database MYDB owner myowner; -drop PostgreSQL database.BE CAREFUL USING THIS COMMAND - IT CANNOT BE REVERSED!! TAKE A BACKUP FIRST drop database MYDB; -list PostgreSQL databases list l -list schemas in a database with psql dn -list schemas in database with postgresql select nspname from pgcatalog.pg.
  • One-page guide to Knex: usage, examples, and more. Knex is an SQL query builder for Node.js.This guide targets v0.13.0.

To check postgresql version:

source: https://stackoverflow.com/a/13733856

To create a super suer with passowrd:

To create a database on Postgresql:

To remove an extension:

To connect to remote psql host 1:

To backup a psql database without typing password 2:

Cheat sheet postgresql example

To create database from sql file:

to backup a single table:

to export a sql statement output to a csv file with header:

to export a sql statement output to a geojson file:

to export a table to a csv file::

COPY current_relation_members TO '/var/lib/postgresql/csv/current_relation_members.CSV' DELIMITER ',' CSV HEADER;

The following are the Meta-Commands for psql command. This can be used with either with -c flag of the psql command like:

Or within the interactive prompt that comes after sudo -u postgres psql command. There are many Meta-Commands and there are available in the psql document. Bellow are a few useful most useful for me:

  • connect to a database: c $DATEBASE_NAME

  • list all users: du

  • list all database: l or list

  • list all table: dt

To allow remote connections to PostgreSQL database server, first check listen_addresses in postgresql.conf:

The output would show something like this:

Now let's edit the postgresql.conf file in our editor of choice:

Search for listen_addresses, and set it to '*' for all addresses or comma separated IP address, save the file and exit. Now we need to change the pg_hba.conf file so let's open it with our editor:

More details here PostgreSQL: Documentation: Connections and Authentication.

Now add the following to the end of file:

Now save the file and exit. Now restart PostgreSQL:

OR:

source: https://bosnadev.com/2015/12/15/allow-remote-connections-postgresql-database-server/

Now connect to the remote server:

source: https://askubuntu.com/a/423181

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Starting the server

Windows Users

You must do this every time you restart your machine.

Mac Users

After you have run this command the first time, postgres will start automatically whenever you boot up your computer.

Starting the postgres shell

Open the shell and connect to the city_explorer database:

psql city_explorer

With no arguments, psql will start the shell connected to your user-default database.

Creating a database

This will create a new database called “book_wiki”, which can contain many individual tables:

CREATE DATABASE book_wiki;

Quit the postgres shell

Type the backslash character, immediatly followed by a “q”:

yourname=# q

Basic shell navigation

List all of your databases

yourname=# l

Connect to a database

yourname=# c book_wiki

List all tables (aka: relations) in the database

yourname=# dt

The command dt means “describe table”.

Display the schema for a table

yourname=# d table-name

Troubleshooting Tips

Cheat Sheet Postgresql

Error - psql not connected to server

psql: could not connect to server: No such file or directory

Solution - Turn Postgres On

See above notes about starting the server.

Error - schema.sql file not found

Postgresql Cheat Sheet Pdf

When connecting your schema.sql to your database:

schema.sql: No such file or directory

Postgresql Sql Cheat Sheet

Solution

Psql Cheat Sheet Pdf

You must specify the full path to the .sql file or run the command from the same directory where the .sql file lives.