ModuleNotFoundError: No module named 'psycopg2' in Python

ModuleNotFoundError: No module named 'psycopg2' in Python #

The Python "ModuleNotFoundError: No module named 'psycopg2'" occurs when we forget to install the psycopg2-binary module before importing it or install it in an incorrect environment. To solve the error, install the module by running the pip install psycopg2-binary command.

Open your terminal in your project's root directory and install the psycopg2-binary module.

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# 👇️ in a virtual environment or using Python 2
pip install psycopg2-binary

# 👇️ for python 3 (could also be pip3.10 depending on your version)
pip3 install psycopg2-binary

# 👇️ if you get permissions error
sudo pip3 install psycopg2-binary
pip install psycopg2-binary --user

# 👇️ if you don't have pip in your PATH environment variable
python -m pip install psycopg2-binary

# 👇️ for python 3 (could also be pip3.10 depending on your version)
python3 -m pip install psycopg2-binary

# 👇️ using py alias (Windows)
py -m pip install psycopg2-binary

# 👇️ for Anaconda
conda install -c conda-forge psycopg2-binary

# 👇️ Alternative for macOS
brew install postgresql

# 👇️ alternative for Debian (Ubuntu)
sudo apt install build-essential libpq-dev python3-dev
pip3 install psycopg2

# 👇️ alternative for Red Hat / CentOS / Fedora
sudo yum install python3-devel postgresql-devel
pip3 install psycopg2

# 👇️ for Jupyter Notebook
!pip install psycopg2-binary

The psycopg2-binary module is a stand-alone package that doesn't require a compiler or external libraries.

After you install the psycopg2-binary package, try importing it as follows.

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import psycopg2

# Connect to your postgres DB
conn = psycopg2.connect("dbname=test user=postgres")

# Open a cursor to perform database operations
cur = conn.cursor()

# Execute a query
cur.execute("SELECT * FROM my_data")

# Retrieve query results
records = cur.fetchall()

The Python error "ModuleNotFoundError: No module named 'psycopg2'" occurs for multiple reasons:

1. Not having the psycopg2-binary package installed by running pip install psycopg2-binary.
2. Installing the package in a different Python version than the one you're using.
3. Installing the package globally and not in your virtual environment.
4. Your IDE running an incorrect version of Python.
5. Naming your module psycopg2.py which would shadow the official module.
6. Declaring a variable named psycopg2 which would shadow the imported variable.

If the error persists, get your Python version and make sure you are installing the package using the correct Python version.

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python --version

For example, my Python version is 3.10.4, so I would install the psycopg2-binary package with pip3.10 install psycopg2-binary.

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pip3.10 install psycopg2-binary

# 👇️ if you get permissions error use pip3 (NOT pip3.X)
sudo pip3 install psycopg2-binary

Notice that the version number corresponds to the version of pip I'm using.

If the PATH for pip is not set up on your machine, replace pip with python3 -m pip:

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# 👇️ make sure to use your version of Python, e.g. 3.10
python3 -m pip install psycopg2-binary

If the "No module named 'psycopg2'" error persists, try restarting your IDE and development server/script.

You can check if you have the psycopg2-binary package installed by running the pip show psycopg2-binary command.

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# 👇️ check if you have psycopg2-binary installed
pip3 show psycopg2-binary

# 👇️ if you don't have pip set up in PATH
python3 -m pip show psycopg2-binary

The pip show psycopg2-binary command will either state that the package is not installed or show a bunch of information about the package, including the location where the package is installed.

If the package is not installed, make sure your IDE is using the correct version of Python.

For example, In VSCode, you can press CTRL + Shift + P or (⌘ + Shift + P on Mac) to open the command palette.

Then type "Python select interpreter" in the field.

Then select the correct python version from the dropdown menu.

If you are using a virtual environment, make sure you are installing psycopg2-binary in your virtual environment and not globally.

You can try creating a virtual environment if you don't already have one.

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# 👇️ use correct version of Python when creating VENV
python3 -m venv venv

# 👇️ activate on Unix or MacOS
source venv/bin/activate

# 👇️ activate on Windows (cmd.exe)
venv\Scripts\activate.bat

# 👇️ activate on Windows (PowerShell)
venv\Scripts\Activate.ps1

# 👇️ install psycopg2-binary in virtual environment
pip install psycopg2-binary

If the python3 -m venv venv command doesn't work, try the following 2 commands:

• python -m venv venv
• py -m venv venv

Your virtual environment will use the version of Python that was used to create it.

You also shouldn't be declaring a variable named psycopg2 as that would also shadow the original module.

If the error is not resolved, try to uninstall the psycopg2-binary package and then install it.

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# 👇️ check if you have psycopg2-binary installed
pip3 show psycopg2-binary

# 👇️ if you don't have pip set up in PATH
python3 -m pip show psycopg2-binary

# 👇️ uninstall psycopg2-binary
pip3 uninstall psycopg2-binary

# 👇️ if you don't have pip set up in PATH
python3 -m pip uninstall psycopg2-binary

# 👇️ install psycopg2-binary
pip3 install psycopg2-binary

# 👇️ if you don't have pip set up in PATH
python3 -m pip install psycopg2-binary

Try restarting your IDE and development server/script.

You can also try to upgrade the version of the psycopg2-binary package.

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pip3 install psycopg2-binary --upgrade

# 👇️ if you don't have pip set up in PATH
python3 -m pip install psycopg2-binary --upgrade

This one is for using virtual environments (VENV) on Windows:

This one is for using virtual environments (VENV) on MacOS and Linux:

Conclusion #

The Python "ModuleNotFoundError: No module named 'psycopg2'" occurs when we forget to install the psycopg2-binary module before importing it or install it in an incorrect environment. To solve the error, install the module by running the pip install psycopg2-binary command.