Add support for aggregated columns in mvt format

lib/cartodb/models/aggregation/aggregation-mapconfig.js

@@ -72,6 +72,18 @@ module.exports = class AggregationMapConfig extends MapConfig {
         });
     }
 
+    getAggregatedColumns (index) {
+        const { aggregation } = this.getLayer(index).options;
+
+        if (aggregation === undefined || aggregation.columns === undefined) {
+            return [];
+        }
+
+        return aggregation.columns
+            .map(({ aggregated_column }) => aggregated_column)
+            .filter(aggregated_column => typeof aggregated_column === 'string');
+    }
+
     isAggregationMapConfig () {
         return this.isVectorOnlyMapConfig() || this.hasAnyLayerAggregation();
     }

lib/cartodb/models/mapconfig/adapter/aggregation-mapconfig-adapter.js

@@ -99,6 +99,10 @@ module.exports = class AggregationMapConfigAdapter {
                     }
 
                     layer.options.sql = aggregationSql;
+
+                    const aggregatedColumns = mapConfig.getAggregatedColumns(index);
+
+                    layer.options.columns = aggregatedColumns;
                 }
 
                 return resolve({ layer, index, adapted: shouldAdapt });