Thanks for coming to the forums – and thank you for asking us at MemSQL to satisfy your curiosity and learning experience
To answer one part of your question – you cannot install MemSQL on a smart phone. There are a few solutions out there where you can use SQL on a mobile phone, like SQLite, but those are usually for mobile applications using SQLite as the storage mechanism.
Apps like Google Sheets actually doesn’t have a “database” installed on the phone. Instead, it’s making a connection to a server somewhere hosted by Google, where Google manages a really powerful system that does the querying for you. Similarly, there are apps you can download on your phone (both on iOS and Android) where you can connect to a database hosted somewhere online so you can run SQL queries on. Again, this isn’t a database installed locally on the phone, but you’re making an internet connection to a database somewhere.
I am not quite sure what your use case is, but using something like Google Sheets is dramatically easier than building a database and running queries on it. Google Sheets does a great job in being a simple “database” – that’s why so many people use it!
Hope this answers your question, and I hope you have fun in your SQL journey!