使用 pip 安装特定的包版本

First, I see two issues with what you're trying to do. Since you already have an installed version, you should either uninstall the current existing driver or use pip install -I MySQL_python==1.2.2

However, you'll soon find out that this doesn't work. If you look at pip's installation log, or if you do a pip install -Iv MySQL_python==1.2.2 you'll find that the PyPI URL link does not work for MySQL_python v1.2.2. You can verify this here: http://pypi.python.org/pypi/MySQL-python/1.2.2

The download link 404s and the fallback URL links are re-directing infinitely due to sourceforge.net's recent upgrade and PyPI's stale URL.

So to properly install the driver, you can follow these steps:

pip uninstall MySQL_python
pip install -Iv http://sourceforge.net/projects/mysql-python/files/mysql-python/1.2.2/MySQL-python-1.2.2.tar.gz/download

I believe that if you already have a package it installed, pip will not overwrite it with another version. Use -I to ignore previous versions.

You can even use a version range with pip install command. Something like this:

pip install 'stevedore>=1.3.0,<1.4.0'

One way as suggested in this post is to mention version in pip as

pip install -Iv MySQL_python==1.2.2

i.e. Use == and mention the version number to install only that version. -I, --ignore-installed ignores already installed packages.

To install a specific python package version whether it is the first time, an upgrade or a downgrade use:

pip install --force-reinstall MySQL_python==1.2.4

MySQL_python version 1.2.2 is not available so I used a different version. To view all available package versions from an index exclude the version:

pip install MySQL_python==

Since this appeared to be a breaking change introduced in version 10 of pip, I downgraded to a compatible version:

pip install 'pip<10' 

This command tells pip to install a version of the module lower than version 10. Do this in a virutalenv so you don't screw up your site installation of Python.