diff --git a/functions/dialect.go b/functions/dialect.go
index 8ff5c65..a238f6c 100644
--- a/functions/dialect.go
+++ b/functions/dialect.go
@@ -7,6 +7,7 @@ import (
 	"io"
 	"strings"
 
+	"github.com/creasty/defaults"
 	"github.com/goccy/go-yaml"
 	substraitgo "github.com/substrait-io/substrait-go"
 	"github.com/substrait-io/substrait-go/extensions"
@@ -187,7 +188,20 @@ type dialectFile struct {
 
 type dialectTypeInfo struct {
 	SqlTypeName       string `yaml:"sql_type_name"`
-	SupportedAsColumn bool   `yaml:"supported_as_column"`
+	SupportedAsColumn bool   `yaml:"supported_as_column" default:"true"`
+}
+
+func (ti *dialectTypeInfo) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type alias dialectTypeInfo
+	aux := &alias{}
+	if err := defaults.Set(aux); err != nil {
+		return err
+	}
+	if err := unmarshal(aux); err != nil {
+		return err
+	}
+	*ti = dialectTypeInfo(*aux)
+	return nil
 }
 
 func (d *dialectFile) getUriAndFunctionName(df *dialectFunction) (string, string) {
diff --git a/functions/types_test.go b/functions/types_test.go
index b9d33fb..c858e99 100644
--- a/functions/types_test.go
+++ b/functions/types_test.go
@@ -99,8 +99,6 @@ supported_types:
     supported_as_column: true
   i64:
     sql_type_name: int64
-    supported_as_column: true
-    supported_as_column: true
   date:
     sql_type_name: DATE
     supported_as_column: true
@@ -112,16 +110,12 @@ supported_types:
     supported_as_column: true
   dec:
     sql_type_name: NUMERIC
-    supported_as_column: true
   vchar:
     sql_type_name: VARCHAR
-    supported_as_column: true
   fchar:
     sql_type_name: CHAR
-    supported_as_column: true
   fbin:
     sql_type_name: BINARY
-    supported_as_column: true
 scalar_functions:
 - name: arithmetic.add
   local_name: +
@@ -182,7 +176,8 @@ scalar_functions:
 			assert.NoError(t, err)
 			assert.Equal(t, tt.localName, localType)
 
-			assert.Equal(t, tt.asColumn, localTypeRegistry.IsTypeSupportedInTables(tt.want))
+			assert.Equal(t, tt.asColumn, localTypeRegistry.IsTypeSupportedInTables(tt.want),
+				"IsTypeSupportedInTables(%s) failed", tt.name)
 		})
 	}