diff --git a/generator/postgres/postgres_generator.go b/generator/postgres/postgres_generator.go
index 08bdb8d..e413abe 100644
--- a/generator/postgres/postgres_generator.go
+++ b/generator/postgres/postgres_generator.go
@@ -80,7 +80,7 @@ func GenerateDB(db *sql.DB, schema, destDir string, templates ...template.Templa
 
 	err = template.ProcessSchema(destDir, schemaMetadata, generatorTemplate)
 	if err != nil {
-		return fmt.Errorf("failed to generate schema %s: %d", schemaMetadata.Name, err)
+		return fmt.Errorf("failed to generate schema %s: %w", schemaMetadata.Name, err)
 	}
 
 	return nil
diff --git a/qrm/qrm.go b/qrm/qrm.go
index cf44044..e09d2d9 100644
--- a/qrm/qrm.go
+++ b/qrm/qrm.go
@@ -131,14 +131,12 @@ func queryJson(ctx context.Context, db Queryable, query string, args []interface
 		return 1, err
 	}
 
-	if jsonData == nil {
-		return 1, nil
-	}
+	if jsonData != nil {
+		err = GlobalConfig.JsonUnmarshalFunc(jsonData, &destPtr)
 
-	err = GlobalConfig.JsonUnmarshalFunc(jsonData, &destPtr)
-
-	if err != nil {
-		return 1, fmt.Errorf("jet: invalid json, %w", err)
+		if err != nil {
+			return 1, fmt.Errorf("jet: invalid json, %w", err)
+		}
 	}
 
 	if rows.Next() {
diff --git a/tests/postgres/select_json_test.go b/tests/postgres/select_json_test.go
index 6c19ad3..b03b814 100644
--- a/tests/postgres/select_json_test.go
+++ b/tests/postgres/select_json_test.go
@@ -956,3 +956,13 @@ world",
 }
 `)
 }
+
+func TestSelectJsonObject_NullMoreThanOneRow(t *testing.T) {
+	var dest map[string]any
+
+	_, err := qrm.QueryJsonObj(ctx, db, `
+SELECT NULL::json AS "json"
+UNION ALL
+SELECT NULL::json AS "json"`, nil, &dest)
+	require.ErrorContains(t, err, "jet: query returned more then one row")
+}