An iterator over the flattened columns for a given schema and table.
        Resolves child columns as having the name "parent.child".

def _flat_columns_in_table(self, table):
        """An iterator over the flattened columns for a given schema and table.
        Resolves child columns as having the name "parent.child".
        """
        for col in self._get_dbt_columns_from_bq_table(table):
            flattened = col.flatten()
            for subcol in flattened:
                yield subcol