diff --git a/frontend/src/adapters/gateways/EChartsOptionBuilder/barOptionBuilder.ts b/frontend/src/adapters/gateways/EChartsOptionBuilder/barOptionBuilder.ts
index 89c4821..e4ba8cf 100644
--- a/frontend/src/adapters/gateways/EChartsOptionBuilder/barOptionBuilder.ts
+++ b/frontend/src/adapters/gateways/EChartsOptionBuilder/barOptionBuilder.ts
@@ -149,16 +149,21 @@ export function buildBarOption(
 
   const label = buildLabelConfig(style);
 
-  if ((isGrouped || isStacked) && seriesBinding) {
-    const seriesField = seriesBinding.columnName;
-    const seriesNames = [...new Set(data.map((row) => String(row[seriesField])))];
+  const colorBinding = getBinding(bindings, 'color');
+  const splitField = seriesBinding?.columnName ?? colorBinding?.columnName;
+  const hasSplit = !!splitField;
 
-    const seriesList = seriesNames.map((name, idx) => {
+  if (hasSplit) {
+    // Multi-series: split by series or color field
+    const splitNames = [...new Set(data.map((row) => String(row[splitField])))];
+
+    const seriesList = splitNames.map((name, idx) => {
       const seriesData = categories.map((cat) => {
-        const row = data.find(
-          (r) => String(r[xField]) === cat && String(r[seriesField]) === name,
+        // Sum all matching rows (there may be multiple)
+        const matchingRows = data.filter(
+          (r) => String(r[xField]) === cat && String(r[splitField]) === name,
         );
-        return row ? Number(row[yField]) : 0;
+        return matchingRows.reduce((sum, r) => sum + (Number(r[yField]) || 0), 0);
       });
 
       return {
@@ -183,9 +188,10 @@ export function buildBarOption(
     option.series = seriesList;
     option.tooltip = { trigger: 'axis' };
   } else {
+    // Single series: aggregate by x category
     const seriesData = categories.map((cat) => {
-      const row = data.find((r) => String(r[xField]) === cat);
-      return row ? Number(row[yField]) : 0;
+      const matchingRows = data.filter((r) => String(r[xField]) === cat);
+      return matchingRows.reduce((sum, r) => sum + (Number(r[yField]) || 0), 0);
     });
 
     if (isHorizontal) {