transformSingle
internal fun <A, B> SingleColumn<A>.transformSingle(converter: (ColumnWithPath<A>) -> List<ColumnWithPath<B>>): ColumnSet<B>
Applies a transformation on this SingleColumn by converting its single ColumnWithPath<A> to List<ColumnWithPath<B>] using converter. Since converter allows you to return multiple columns, the result is turned into a ColumnSet<B>.