It does depend on what we're talking about when we say functions. If you're talking in-line table functions or multi-statement table valued functions that are created within SQL Server, then those are executed on SQL Server. If you're talking about functions within C#, F#, Java, or name your programming language, and we're not talking about Common Language Runtime (CLR) functions, then those functions are executed on the client. But we have to define the terms better to know which is right.