Major Description
Quoted from jdere "in the case that getCellValueTransformer() returns a constant value (such as "NULL" to indicate the expression should be null), the resulting data type for that column ends up becoming the constant value NULL, which is different from the original column's type. Might want to add a type check somewhere to make sure the transformed expression and original expression match, or maybe wrap the transformed expression within a CAST to get the types to match."