How to create tables from external files Excel or others using Latex

http://quicklatex.blogspot.com is a collection of video tutorials. Latex can be used to create tables from external files such as MS-Excel files saved as comma separated values or similarly many other formats. Recently, I received a comment where a reader suggested that I should post a tutorial on how to create tables in Latex from external files. I searched around and found multiple ways to achieve this. I am going to talk about two of the most popular ways of doing it. First one is using pgfplotstable and the second one is using datatool package.