A Function is a mapping embodied as a program (the function body) that can be invoked by using zero or more input values (arguments) to a single value (the result). A User-defined function (UDF) is a way to extend MySQL with a new function that works like native (built-in) MySQL functions such as ABS() and CONCAT(). UDFs must be created on the server machine.
UDF Editor allows you to define user-defined function properties. It opens automatically when you create a new user-defined function and is available on editing an existing one.
To open a user-defined function in UDF Editor, double-click it in the DB Explorer tree.