diff --git a/lib/cartodb/models/aggregation/aggregation-query.js b/lib/cartodb/models/aggregation/aggregation-query.js
index bf995c82..ca6d3431 100644
--- a/lib/cartodb/models/aggregation/aggregation-query.js
+++ b/lib/cartodb/models/aggregation/aggregation-query.js
@@ -46,20 +46,27 @@ const SUPPORTED_AGGREGATE_FUNCTIONS = {
     },
     'max': {
         sql: (column_name, params) => `max(${params.aggregated_column || column_name})`
+    },
+    'mode': {
+        sql: (column_name, params) => `cdb_mode(${params.aggregated_column || column_name})`
     }
 };
 
 const aggregateColumns = ctx => {
-    // TODO: always add count
-    let columns = ctx.columns || {};
-    if (Object.keys(columns).length === 0) {
-        // default aggregation
-        columns = {
-            _cdb_feature_count: {
-                aggregate_function: 'count'
-            }
-        };
-    }
+    return Object.assign({
+        _cdb_feature_count: {
+            aggregate_function: 'count'
+        }
+    }, ctx.columns || {});
+};
+
+const aggregateColumnNames = ctx => {
+    let columns = aggregateColumns(ctx);
+    return Object.keys(columns).join(', ');
+};
+
+const aggregateColumnDefs = ctx => {
+    let columns = aggregateColumns(ctx);
     return Object.keys(columns).map(column_name => {
         const aggregate_function = columns[column_name].aggregate_function || 'count';
         const aggregate_definition = SUPPORTED_AGGREGATE_FUNCTIONS[aggregate_function];
@@ -94,7 +101,7 @@ const aggregationQueryTemplates = {
                     AVG(ST_Y(_cdb_query.the_geom_webmercator))
                 ), 3857
             ) AS the_geom_webmercator,
-            ${aggregateColumns(ctx)}
+            ${aggregateColumnDefs(ctx)}
         FROM (${ctx.sourceQuery}) _cdb_query, _cdb_params
         WHERE _cdb_query.the_geom_webmercator && _cdb_params.bbox
         GROUP BY
@@ -112,14 +119,14 @@ const aggregationQueryTemplates = {
         SELECT
         Floor(ST_X(_cdb_query.the_geom_webmercator)/_cdb_params.res)::int AS _cdb_gx,
         Floor(ST_Y(_cdb_query.the_geom_webmercator)/_cdb_params.res)::int AS _cdb_gy,
-        ${aggregateColumns(ctx)}
+        ${aggregateColumnDefs(ctx)}
         FROM (${ctx.sourceQuery}) _cdb_query, _cdb_params
         WHERE the_geom_webmercator && _cdb_params.bbox
         GROUP BY _cdb_gx, _cdb_gy
     )
     SELECT
         ST_SetSRID(ST_MakePoint(_cdb_gx*(res+0.5), _cdb_gy*(res+0.5)), 3857) AS the_geom_webmercator,
-        _cdb_feature_count
+        ${aggregateColumnNames(ctx)}
         FROM _cdb_clusters, _cdb_params
     `,
 
@@ -132,7 +139,7 @@ const aggregationQueryTemplates = {
         ), _cdb_clusters AS (
             SELECT
                 MIN(cartodb_id) AS cartodb_id,
-                ${aggregateColumns(ctx)}
+                ${aggregateColumnDefs(ctx)}
             FROM (${ctx.sourceQuery}) _cdb_query, _cdb_params
             WHERE _cdb_query.the_geom_webmercator && _cdb_params.bbox
             GROUP BY
@@ -141,7 +148,7 @@ const aggregationQueryTemplates = {
         ) SELECT
             _cdb_clusters.cartodb_id,
             the_geom, the_geom_webmercator,
-            _cdb_feature_count
+            ${aggregateColumnNames(ctx)}
         FROM
             _cdb_clusters INNER JOIN (${ctx.sourceQuery}) _cdb_query
             ON (_cdb_clusters.cartodb_id = _cdb_query.cartodb_id)
diff --git a/test/acceptance/aggregation.js b/test/acceptance/aggregation.js
index 46ea56b0..aa245fac 100644
--- a/test/acceptance/aggregation.js
+++ b/test/acceptance/aggregation.js
@@ -20,6 +20,7 @@ describe('aggregation', function () {
 
     const POINTS_SQL_1 = `
     select
+        x + 4 as cartodb_id,
         st_setsrid(st_makepoint(x*10, x*10), 4326) as the_geom,
         st_transform(st_setsrid(st_makepoint(x*10, x*10), 4326), 3857) as the_geom_webmercator,
         x as value
@@ -28,6 +29,7 @@ describe('aggregation', function () {
 
     const POINTS_SQL_TIMESTAMP_1 = `
     select
+        row_number() over() AS cartodb_id,
         st_setsrid(st_makepoint(x*10, x*10), 4326) as the_geom,
         st_transform(st_setsrid(st_makepoint(x*10, x*10), 4326), 3857) as the_geom_webmercator,
         x as value,
@@ -41,6 +43,7 @@ describe('aggregation', function () {
 
     const POINTS_SQL_2 = `
     select
+        x + 4 as cartodb_id,
         st_setsrid(st_makepoint(x*10, x*10*(-1)), 4326) as the_geom,
         st_transform(st_setsrid(st_makepoint(x*10, x*10*(-1)), 4326), 3857) as the_geom_webmercator,
         x as value,
@@ -50,6 +53,7 @@ describe('aggregation', function () {
 
     const POLYGONS_SQL_1 = `
     select
+        x + 4 as cartodb_id,
         st_buffer(st_setsrid(st_makepoint(x*10, x*10), 4326)::geography, 100000)::geometry as the_geom,
         st_transform(
             st_buffer(st_setsrid(st_makepoint(x*10, x*10), 4326)::geography, 100000)::geometry,