diff --git a/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.test.tsx b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.test.tsx
new file mode 100644
index 00000000000..55dac72aa8d
--- /dev/null
+++ b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.test.tsx
@@ -0,0 +1,137 @@
+import React from 'react';
+import { selectOptionInTest } from '@grafana/ui';
+import { act, render, screen } from '@testing-library/react';
+import { CloudWatchMetricsQuery, MetricEditorMode, MetricQueryType, SQLExpression } from '../../types';
+import { setupMockedDataSource } from '../../__mocks__/CloudWatchDataSource';
+import { QueryEditorExpressionType, QueryEditorPropertyType } from '../../expressions';
+import SQLBuilderSelectRow from './SQLBuilderSelectRow';
+
+const { datasource } = setupMockedDataSource();
+
+const makeSQLQuery = (sql?: SQLExpression): CloudWatchMetricsQuery => ({
+  queryMode: 'Metrics',
+  refId: '',
+  id: '',
+  region: 'us-east-1',
+  namespace: 'ec2',
+  dimensions: { somekey: 'somevalue' },
+  metricQueryType: MetricQueryType.Query,
+  metricEditorMode: MetricEditorMode.Builder,
+  sql: sql,
+});
+
+const query = makeSQLQuery({
+  select: {
+    type: QueryEditorExpressionType.Function,
+    name: 'AVERAGE',
+    parameters: [
+      {
+        type: QueryEditorExpressionType.FunctionParameter,
+        name: 'm1',
+      },
+    ],
+  },
+  from: {
+    type: QueryEditorExpressionType.Property,
+    property: {
+      type: QueryEditorPropertyType.String,
+      name: 'n1',
+    },
+  },
+});
+
+const onQueryChange = jest.fn();
+const baseProps = {
+  query,
+  datasource,
+  onQueryChange,
+};
+
+const namespaces = [
+  { value: 'n1', label: 'n1', text: 'n1' },
+  { value: 'n2', label: 'n2', text: 'n2' },
+];
+const metrics = [
+  { value: 'm1', label: 'm1', text: 'm1' },
+  { value: 'm2', label: 'm2', text: 'm2' },
+];
+
+describe('Cloudwatch SQLBuilderSelectRow', () => {
+  beforeEach(() => {
+    datasource.getNamespaces = jest.fn().mockResolvedValue(namespaces);
+    datasource.getMetrics = jest.fn().mockResolvedValue([]);
+    datasource.getDimensionKeys = jest.fn().mockResolvedValue([]);
+    datasource.getDimensionValues = jest.fn().mockResolvedValue([]);
+    onQueryChange.mockReset();
+  });
+
+  it('Should not reset metricName when selecting a namespace if metric exist in new namespace', async () => {
+    datasource.getMetrics = jest.fn().mockResolvedValue(metrics);
+
+    await act(async () => {
+      render(<SQLBuilderSelectRow {...baseProps} />);
+    });
+
+    expect(screen.getByText('n1')).toBeInTheDocument();
+    expect(screen.getByText('m1')).toBeInTheDocument();
+    const namespaceSelect = screen.getByLabelText('Namespace');
+    await selectOptionInTest(namespaceSelect, 'n2');
+
+    const expectedQuery = makeSQLQuery({
+      select: {
+        type: QueryEditorExpressionType.Function,
+        name: 'AVERAGE',
+        parameters: [
+          {
+            type: QueryEditorExpressionType.FunctionParameter,
+            name: 'm1',
+          },
+        ],
+      },
+      from: {
+        type: QueryEditorExpressionType.Property,
+        property: {
+          type: QueryEditorPropertyType.String,
+          name: 'n2',
+        },
+      },
+    });
+    expect(onQueryChange).toHaveBeenCalledTimes(1);
+    expect(onQueryChange.mock.calls).toEqual([[{ ...expectedQuery, namespace: 'n2' }]]);
+  });
+
+  it('Should reset metricName when selecting a namespace if metric does not exist in new namespace', async () => {
+    datasource.getMetrics = jest.fn().mockImplementation((namespace: string, region: string) => {
+      let mockMetrics =
+        namespace === 'n1' && region === baseProps.query.region
+          ? metrics
+          : [{ value: 'newNamespaceMetric', label: 'newNamespaceMetric', text: 'newNamespaceMetric' }];
+      return Promise.resolve(mockMetrics);
+    });
+
+    await act(async () => {
+      render(<SQLBuilderSelectRow {...baseProps} />);
+    });
+
+    expect(screen.getByText('n1')).toBeInTheDocument();
+    expect(screen.getByText('m1')).toBeInTheDocument();
+    const namespaceSelect = screen.getByLabelText('Namespace');
+    await selectOptionInTest(namespaceSelect, 'n2');
+
+    const expectedQuery = makeSQLQuery({
+      select: {
+        type: QueryEditorExpressionType.Function,
+        name: 'AVERAGE',
+      },
+      from: {
+        type: QueryEditorExpressionType.Property,
+        property: {
+          type: QueryEditorPropertyType.String,
+          name: 'n2',
+        },
+      },
+    });
+    expect(onQueryChange).toHaveBeenCalledTimes(1);
+    expect(onQueryChange.mock.calls).toEqual([[{ ...expectedQuery, namespace: 'n2' }]]);
+  });
+});
diff --git a/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.tsx b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.tsx
index 4603329c145..1c49d73aba0 100644
--- a/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.tsx
+++ b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/SQLBuilderSelectRow.tsx
@@ -1,5 +1,5 @@
 import React, { useEffect, useMemo } from 'react';
-import { toOption } from '@grafana/data';
+import { SelectableValue, toOption } from '@grafana/data';
 import { EditorField, EditorFieldGroup } from '@grafana/experimental';
 import { Select, Switch } from '@grafana/ui';
 import { STATISTICS } from '../../cloudwatch-sql/language';
@@ -12,6 +12,7 @@ import {
   getNamespaceFromExpression,
   getSchemaLabelKeys as getSchemaLabels,
   isUsingWithSchema,
+  removeMetricName,
   setAggregation,
   setMetricName,
   setNamespace,
@@ -52,16 +53,32 @@ const SQLBuilderSelectRow: React.FC<SQLBuilderSelectRowProps> = ({ datasource, q
     [unusedDimensionKeys, schemaLabels]
   );
 
+  const onNamespaceChange = async (query: CloudWatchMetricsQuery) => {
+    const validatedQuery = await validateMetricName(query);
+    onQueryChange(validatedQuery);
+  };
+
+  const validateMetricName = async (query: CloudWatchMetricsQuery) => {
+    let { region, sql } = query;
+    await datasource.getMetrics(query.namespace, region).then((result: Array<SelectableValue<string>>) => {
+      if (!result.some((metric) => metric.value === metricName)) {
+        sql = removeMetricName(query).sql;
+      }
+    });
+    return { ...query, sql };
+  };
+
   return (
     <>
       <EditorFieldGroup>
         <EditorField label="Namespace" width={16}>
           <Select
+            aria-label="Namespace"
             value={namespace ? toOption(namespace) : null}
             inputId={`${query.refId}-cloudwatch-sql-namespace`}
             options={namespaceOptions}
             allowCustomValue
-            onChange={({ value }) => value && onQueryChange(setNamespace(query, value))}
+            onChange={({ value }) => value && onNamespaceChange(setNamespace(query, value))}
             menuShouldPortal
           />
         </EditorField>
diff --git a/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/utils.ts b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/utils.ts
index c2901c3a562..a0b28ca62f4 100644
--- a/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/utils.ts
+++ b/public/app/plugins/datasource/cloudwatch/components/SQLBuilderEditor/utils.ts
@@ -146,6 +146,8 @@ export function setSql(query: CloudWatchMetricsQuery, sql: SQLExpression): Cloud
 
 export function setNamespace(query: CloudWatchMetricsQuery, namespace: string | undefined): CloudWatchMetricsQuery {
   const sql = query.sql ?? {};
+  //updating `namespace` props for CloudWatchMetricsQuery
+  query.namespace = namespace ? namespace : '';
 
   if (namespace === undefined) {
     return setSql(query, {
@@ -230,6 +232,13 @@ export function setMetricName(query: CloudWatchMetricsQuery, metricName: string)
   });
 }
 
+export function removeMetricName(query: CloudWatchMetricsQuery): CloudWatchMetricsQuery {
+  const queryWithNoParams = { ...query };
+  delete queryWithNoParams.sql?.select?.parameters;
+
+  return queryWithNoParams;
+}
+
 export function setAggregation(query: CloudWatchMetricsQuery, aggregation: string): CloudWatchMetricsQuery {
   return setSql(query, {
     select: {