I am currently working on a project to read temperatures from multiple points using a sensor and Node MCU setup. I require all these datas (from 16 node MCU) to be stored to a web server. Can I do it without internet. I don't want to do live monitoring but have to store data for few days in the server. I have a Raspberry pi that can be used to create the wifi hotspot and a repeater to extend the range. Sorry if the post is confusing. I am a beginner in this field. Can I implement this? If yes can anyone please outline the steps to be followed?
If you are going to create a Hotspot in Raspberry PI i.e WAP(Wireless access point) and gonna connect all 16 NodeMCUs to it you will have to transform your Raspberry PI into a solid LAMP (Linux, Apache, MySQL, PHP) system with one apt-get invocation. Google Search "Building LAMP server on Raspberry Pi".
Xampp is for the Intel-based computers not ARM Linux based. There is no way you will get it to run on Raspberry Pi.
And If you are just going to connect your 16 NodeMCU to Raspberry PI WAP and then send the data received by Rasberry Pi to the PC having XAMPP on it, it will be difficult and complicated for you.