1、点击PyCharm-Preferences
2、选择Project Interpreter,点击“+”号
3、搜索模块，选择要安装的版本，点击安装
注意：
安装模块如果报错，可能因为开了代理，要关闭代理。
命令安装模块：
yayadeMac:~ ddc-test$ sudo pip3 install PyMySQL
The directory '/Users/ddc-test/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/ddc-test/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Collecting PyMySQL
Downloading https://files.pythonhosted.org/packages/ed/39/15045ae46f2a123019aa968dfcba0396c161c20f855f11dea6796bcaae95/PyMySQL-0.9.3-py2.py3-none-any.whl (47kB)
100% |████████████████████████████████| 51kB 414kB/s
Installing collected packages: PyMySQL
Successfully installed PyMySQL-0.9.3
You are using pip version 10.0.1, however version 19.3.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
yayadeMac:~ ddc-test$ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymysql
>>>
如果没有报错，则表示安装成功。