fix(chart): added Big Number chart support for MAX metric with VARCHAR column

superset-frontend/plugins/plugin-chart-echarts/src/BigNumber/BigNumberTotal/transformProps.test.ts

@@ -231,6 +231,57 @@ describe('BigNumberTotal transformProps', () => {
     expect(result.headerFormatter(500)).toBe('$500');
   });
 
+  test('should pass through non-numeric raw string when parseMetricValue returns null (e.g. VARCHAR MAX)', () => {
+    const { parseMetricValue } = jest.requireMock('../utils');
+    parseMetricValue.mockReturnValueOnce(null);
+
+    const chartProps = {
+      width: 400,
+      height: 300,
+      queriesData: [
+        {
+          data: [{ value: 'some-varchar-result' }],
+          coltypes: [GenericDataType.String],
+        },
+      ],
+      formData: baseFormData,
+      rawFormData: baseRawFormData,
+      hooks: baseHooks,
+      datasource: baseDatasource,
+    };
+
+    const result = transformProps(
+      chartProps as unknown as BigNumberTotalChartProps,
+    );
+    expect(result.bigNumber).toBe('some-varchar-result');
+  });
+
+  test('should not fall back to raw string when value is numeric-looking VARCHAR (e.g. "123")', () => {
+    const { parseMetricValue } = jest.requireMock('../utils');
+    parseMetricValue.mockReturnValueOnce(null);
+
+    const chartProps = {
+      width: 400,
+      height: 300,
+      queriesData: [
+        {
+          data: [{ value: '123' }],
+          coltypes: [GenericDataType.String],
+        },
+      ],
+      formData: baseFormData,
+      rawFormData: baseRawFormData,
+      hooks: baseHooks,
+      datasource: baseDatasource,
+    };
+
+    const result = transformProps(
+      chartProps as unknown as BigNumberTotalChartProps,
+    );
+    // parsedValue is null and "123" is numeric, so bigNumber stays null (not "123")
+    expect(result.bigNumber).toBeNull();
+  });
+
   test('should propagate colorThresholdFormatters from getColorFormatters', () => {
     // Override the getColorFormatters mock to return specific value
     const mockFormatters = [{ formatter: 'red' }];

superset-frontend/plugins/plugin-chart-echarts/src/BigNumber/BigNumberTotal/transformProps.ts

@@ -79,8 +79,16 @@ export default function transformProps(
   const formattedSubtitleFontSize = subtitle?.trim()
     ? (subtitleFontSize ?? PROPORTION.SUBHEADER)
     : (subheaderFontSize ?? subtitleFontSize ?? PROPORTION.SUBHEADER);
+  const rawValue = data.length === 0 ? null : data[0][metricName];
+  const parsedValue = rawValue == null ? null : parseMetricValue(rawValue);
+
   const bigNumber =
-    data.length === 0 ? null : parseMetricValue(data[0][metricName]);
+    parsedValue === null &&
+    typeof rawValue === 'string' &&
+    rawValue !== '' &&
+    Number.isNaN(Number(rawValue))
+      ? rawValue
+      : parsedValue;
 
   let metricEntry: Metric | undefined;
   if (chartProps.datasource?.metrics) {