关于pyqt5安装失败有很多问题，有python版本问题，比如这篇文章介绍的:python pyqt5安装失败问题,这个解决方案对我没用，我的python是版本3.7，已经高于3.4。最后发现是pip版本有问题，更新到新版pip就可以下载成功了。
报的错误：
Could not find a version that satisfies the requirement sip<7,>=6.4
(from versions: 4.19.7, 4.19.8, 5.0.0, 5.0.1, 5.1.0, 5.1.1, 5.1.2,
5.2.0, 5.3.0, 5.4.0, 5.5.0, 6.0.0, 6.0.1, 6.0.2, 6.0.3, 6.1.0, 6.1.1, 6.2.0) No matching distribution found for sip<7,>=6.4
下面提示了
“You are using pip version 10.0.1, however version 22.1.2 is
available. You should consider upgrading via the ‘python -m pip
install --upgrade pip’ command.”
这时更新一下pip：python -m pip install --upgrade pip --user
pip版本更新成功后，重新下载pyqt5也成功了：pip install PyQt5
