Installing psql on Mac, Ubuntu, Debian, Windows
psql
is the standard command line interface for interacting with a PostgreSQL or TimescaleDB instance. Here we explain how to install psql
on various platforms.
Before you start, you should confirm that you don’t already have psql
installed. In fact, if you’ve ever installed Postgres or TimescaleDB before, you likely already have psql
installed.
psql --version
If your client doesn’t have psql
installed, find the appropriate section below for OS specific instructions on how to install it.
MacOS using Homebrew
First, install the Brew Package Manager. Homebrew simplifies the installation of software on macOS.
Second, update brew
. From your command line, run the following commands:
brew doctor
brew update
brew install libpq
Finally, create a symbolic link to psql
(and other libpq
tools) into /usr/local/bin
so that you can reach it from any command on the macOS Terminal.
brew link --force libpq ail
Ubuntu 16.04,18.04,20.04 and Debian 9,10
Install on Ubuntu and Debian using the apt
package manager:
sudo apt-get update
sudo apt-get install postgresql-client
tip
This only installs the psql
client and not the PostgreSQL database.
Windows 10
We recommend using the installer from PostgreSQL.org.
Connect to your PostgreSQL server
In order to connect to your PostgreSQL server, you’ll need the following connection parameters:
- Hostname
- Port
- Username
- Password
- Database name
There are two ways to use these parameters to connect to your PostgreSQL database.
Option 1: Supply parameters at the command line
In this method, use parameter flags on the command line to supply the required information to connect to a PostgreSQL database:
psql -h HOSTNAME -p PORT -U USERNAME -W -d DATABASENAME
Once you run that command, the prompt will ask you for your password. (This is the purpose of the -W
flag.)
Option 2: Use a service URI
The Service URI begins with postgres://
.
psql postgres://[USERNAME]:[PASSWORD]@[HOSTNAME]:[PORT]/[DATABASENAME]?sslmode=require
Fun things to do with psql
Common psql commands
Here is a table of common commands you’ll find yourself using a lot:
Command | Actions |
---|---|
\l | List available databases |
\c dbname | Connect to a new database |
\dt | List available tables |
\d tablename | Describe the details of given table |
\dn | List all schemas in the current database |
\df | List functions in the current database |
\h | Get help on syntax of SQL commands |
\? | Lists all psql slash commands |
\set | System variables list |
\timing | Shows how long a query took to execute |
\x | Show expanded query results |
\q | Quit psql |
Save results of a query to a comma-separated file
You may often find yourself running SQL queries with lengthy results. You can save these results to a comma-separated file (CSV) using the COPY
command:
\copy (SELECT * FROM ...) TO '/tmp/myoutput.csv' (format CSV);
You would then be able to open /tmp/myoutput.csv
using any spreadsheet or similar program that reads CSV files.
Edit a SQL query in an editor
Sometimes you may find yourself writing a lengthy query such as this one below:
-- For each airport: num trips, avg trip duration, avg cost, avg tip, avg distance, min distance, max distance, avg number of passengers
SELECT rates.description, COUNT(vendor_id) AS num_trips,
AVG(dropoff_datetime - pickup_datetime) AS avg_trip_duration, AVG(total_amount) AS avg_total,
AVG(tip_amount) AS avg_tip, MIN(trip_distance) AS min_distance, AVG (trip_distance) AS avg_distance, MAX(trip_distance) AS max_distance,
AVG(passenger_count) AS avg_passengers
FROM rides
JOIN rates ON rides.rate_code = rates.rate_code
WHERE rides.rate_code IN (2,3) AND pickup_datetime < '2016-02-01'
GROUP BY rates.description
ORDER BY rates.description;
It would be pretty common to make an error the first couple of times you attempt to write something that long in SQL. Instead of re-typing every line or character, you can launch a vim
editor using the \e
command. Your previous command can then be edited, and once you save (“Escape-Colon-W-Q”) your edits, the command will appear in the buffer. You will be able to get back to it by pressing the up arrow in your Terminal window.
Congrats! Now you have connected via psql
.