If you are new to a certain coding language, or continuously switching between various, this site has more than 45 compilers for you to test small or big codes.
From the traditional Java, C, C++, C#, Python to the more exotic Elixir, Erlang or old Cobol souvenirs.
It does also the web languages so as 9 databases queries interaction. It that later case, having defined a database sample to reuse will be a must for complex queries development.
Free, No registration, No Download/Install required