If an entire column is null, which data type will be assigned by the Auto Field Tool?

When using the Auto Field Tool in Alteryx, if an entire column is null, it assigns the data type as String. This is because, in the case of completely null values, there is no numeric or datetime information to derive a more specific type, which typically would include Integers, Bools, or DateTimes. The tool opts for String as a default, as Strings can encompass a broader range of values and are suitable for representing potentially varied or missing data. Assigning String allows for greater flexibility in handling null values without assuming a more specific type that cannot be supported. Consequently, when all entries in a column are identified as null, the safest choice is to treat the column as a text type, hence leading to its assignment as String.