数据分析相关的各种说明文档

numpy:
https://docs.scipy.org/doc/numpy/reference/

pandas:
https://pandas.pydata.org/pandas-docs/stable/index.html

matplotlib:
https://matplotlib.org/2.2.2/index.html

SQL语法 from postgresql(version:8.1):
https://www.postgresql.org/docs/8.1/static/functions.html