Changing typecast of unknown column types

There are instances when columns can take on an unknown typecast denoted by a ? Icon next to the column name. This often happens after transposes or unpivoting. I am unsure why this happens, if a column contains numbers as well as text surely it should be denoted as string typecast.

handling these unknown column types in subsequent nodes is tricky. I would have hoped that there would be nodes to easily convert these, but that doesn't seem the case.

is it possible to have a node like string to number node, which changes typecast, but obviously have ones called unknown typecast to string, and unknown typecast to double.

this would significantly improve column handling.

thanks,

simon.