解决方法如下：
1.首先卸载已经安装python3-pip
sudo apt remove python3-pip
2.安装python3.8-pip
sudo python3.8 -m easy_install pip
3.安装sqlalchemy
wang@wang:~$ sudo pip3.8 install sqlalchemy标签：Ubuntu20.04,sqlalchemy,wang,1.3,报错,cp38,安装,python3 From： https://blog.51cto.com/u_13753753/5928541
Collecting sqlalchemy
Downloading SQLAlchemy-1.3.20-cp38-cp38-manylinux2010_x86_64.whl (1.3 MB)
|████████████████████████████████| 1.3 MB 40 kB/s
Installing collected packages: sqlalchemy
Successfully installed sqlalchemy-1.3.20
wang@wang:~$