put it this way, it's more of the code then and the connection then it is about the database. SQL has more menu and orientation that deals with Visual Studio, while MySql is more command line driven.
further, PHP uses more HTML which ASP.NET uses the <ASP> tag for all their browser items. And finally the Code. ASP.NET will use Visual Basic a wordy type of code and also C# where the code is more Java based.
PHP on the other hand uses a more structured code like C++, but there's the newer the version, the more pre-compiled functions to allow users and programers more flexibility with simple things like email.
To my knowledge, if you are new to programming period. Start with PHP. It's free, there are tons of service programs for Windows XP, etc or even for Linux (LAMP) installations. If you are a Microsoft person, have the $$$ for Visual Studio, and are looking to go into .NET, then by all means learn .NET from the start.