Call custom select if translation is not possible.

[AlienEngineer]

As suggested by @BRUNOSS.

Enable select calls to be made on mapping when the translation is not supported or not possible at all.

// A non supported query
Query<Employee>().Select(e => e.LastName.Split(';')[0]);

Should translate as:

Select [T0].[LastName] From [Employees] [T0]

//this function has to be called on each mapping.
Func<Employee> map = e => e.LastName.Split(';')[0];