How to run raw SELECT for a Base field?

Hello,

I have a class extending `Base` that has one field that's quite complex to retrieve - I want to run a complex SELECT (one that has a JOIN on another table where ID is a string that has to be converted to int and is back JOIN-ed to the original table using that ID). It seems like its simply impossible to retrieve the value for this field using only `relationship` and keep it only one field (and not a structure with multiple { }).

Is it possible to run a raw SQL to retrieve a field value?

Thanks