Checking your PostgreSQL Version

How to Check PostgreSQL Version?

To determine which version of PostgreSQL is running, there are multiple commands and options you can use within the psql command-line interface or directly from your system's command line. Here’s a guide on checking the PostgreSQL version.

1. Using SHOW server_version in psql

The SHOW server_version command is a quick way to check the server version when connected to psql.

Syntax:

SHOW server_version;

Example Code:

-- Display the PostgreSQL server version
SHOW server_version;  -- Outputs the version of the PostgreSQL server

Explanation:

• SHOW server_version;: Displays the server's version. This command is useful when you are already connected to a PostgreSQL database.

2. Using the psql --version Command in the Terminal

If you want to check the version of the psql client (PostgreSQL client), you can use the --version option in your command line.

Syntax:

psql --version

Example Code:

# Check the psql client version from the command line
psql --version   # Outputs the version of the psql client

Explanation:

• psql --version: Displays the version of the psql client, which might be different from the server version if multiple PostgreSQL versions are installed.

3. Using the SELECT version() Command in psql

The SELECT version(); command provides a detailed output with both the PostgreSQL version and additional system information.

Syntax:

SELECT version();

Example Code:

-- Run a query to get the PostgreSQL version and server details
SELECT version();  -- Outputs the full PostgreSQL server version and system information

Explanation:

• SELECT version();: Returns the complete server version, including the version number and additional details about the build and system. This is useful for getting full information about the PostgreSQL installation.

Important Notes

• Client vs. Server Versions: The psql --version command checks the client version, while SHOW server_version; and SELECT version(); check the server version. Ensure you’re looking at the correct version based on your needs.
• Access Permissions: You need access to a database to use SHOW server_version or SELECT version(); within psql.