There is no straight answer.
If you are playing around with programming for yourself, then you have the liberty to choose the programming language. There are languages that are more suited for certain tasks.
E.g. performance critical tasks are often written in C/C++, but even Assembly and micro controllers are considered for certain tasks.
If you want to quickly create UI, the C# is a good choice.
For Web programming, you'll need to know HTML, CSS, Java Script, you can use C#, Python Java and many more languages.
If you want platform independent code, you'll look for C/C++, Java, Python, Go, etc.
Do you need databases? You'll probably need to know some sort of SQL.
However, if you go and work for a company, most probably their technical leaders have already decided on a language(s) to use. It's highly probable that you won't start from scratch, but join a team who has a code base already.