diff --git a/superset/db_engine_specs/base.py b/superset/db_engine_specs/base.py
index f924ade58e..4ed9ec5e44 100644
--- a/superset/db_engine_specs/base.py
+++ b/superset/db_engine_specs/base.py
@@ -902,16 +902,18 @@ class BaseEngineSpec:  # pylint: disable=too-many-public-methods
         return label_mutated
 
     @classmethod
-    def get_sqla_column_type(cls, type_: str) -> Optional[TypeEngine]:
+    def get_sqla_column_type(cls, type_: Optional[str]) -> Optional[TypeEngine]:
         """
         Return a sqlalchemy native column type that corresponds to the column type
         defined in the data source (return None to use default type inferred by
-        SQLAlchemy). Override `_column_type_mappings` for specific needs
+        SQLAlchemy). Override `column_type_mappings` for specific needs
         (see MSSQL for example of NCHAR/NVARCHAR handling).
 
         :param type_: Column type returned by inspector
         :return: SqlAlchemy column type
         """
+        if not type_:
+            return None
         for regex, sqla_type in cls.column_type_mappings:
             match = regex.match(type_)
             if match:
diff --git a/superset/db_engine_specs/presto.py b/superset/db_engine_specs/presto.py
index 9b2c47b307..bb8461311f 100644
--- a/superset/db_engine_specs/presto.py
+++ b/superset/db_engine_specs/presto.py
@@ -174,7 +174,9 @@ class PrestoEngineSpec(BaseEngineSpec):
         return [row[0] for row in results]
 
     @classmethod
-    def _create_column_info(cls, name: str, data_type: str) -> Dict[str, Any]:
+    def _create_column_info(
+        cls, name: str, data_type: types.TypeEngine
+    ) -> Dict[str, Any]:
         """
         Create column info object
         :param name: column name
@@ -265,8 +267,11 @@ class PrestoEngineSpec(BaseEngineSpec):
                         # overall structural data type
                         column_type = cls.get_sqla_column_type(field_info[1])
                         if column_type is None:
-                            raise NotImplementedError(
-                                _("Unknown column type: %(col)s", col=field_info[1])
+                            column_type = types.String()
+                            logger.info(
+                                "Did not recognize type %s of column %s",
+                                field_info[1],
+                                field_info[0],
                             )
                         if field_info[1] == "array" or field_info[1] == "row":
                             stack.append((field_info[0], field_info[1]))
@@ -381,8 +386,11 @@ class PrestoEngineSpec(BaseEngineSpec):
             # otherwise column is a basic data type
             column_type = cls.get_sqla_column_type(column.Type)
             if column_type is None:
-                raise NotImplementedError(
-                    _("Unknown column type: %(col)s", col=column_type)
+                column_type = types.String()
+                logger.info(
+                    "Did not recognize type %s of column %s",
+                    str(column.Type),
+                    str(column.Column),
                 )
             column_info = cls._create_column_info(column.Column, column_type)
             column_info["nullable"] = getattr(column, "Null", True)
diff --git a/tests/db_engine_specs/presto_tests.py b/tests/db_engine_specs/presto_tests.py
index 3a0346bfe2..7045fc34ec 100644
--- a/tests/db_engine_specs/presto_tests.py
+++ b/tests/db_engine_specs/presto_tests.py
@@ -511,3 +511,6 @@ class TestPrestoDbEngineSpec(TestDbEngineSpec):
 
         sqla_type = PrestoEngineSpec.get_sqla_column_type("integer")
         assert isinstance(sqla_type, types.Integer)
+
+        sqla_type = PrestoEngineSpec.get_sqla_column_type(None)
+        assert sqla_type is None