diff --git a/x-pack/plugins/transform/public/app/common/request.ts b/x-pack/plugins/transform/public/app/common/request.ts
index 79fb3acb9fcaf..7e965dbe802c0 100644
--- a/x-pack/plugins/transform/public/app/common/request.ts
+++ b/x-pack/plugins/transform/public/app/common/request.ts
@@ -81,7 +81,7 @@ export function getPreviewRequestBody(
     },
   };
 
-  if (!isDefaultQuery(query)) {
+  if (!isDefaultQuery(query) && !isMatchAllQuery(query)) {
     request.source.query = query;
   }
 
diff --git a/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_form.tsx b/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_form.tsx
index df22c3f3eb2e2..5e0eb7ee08361 100644
--- a/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_form.tsx
+++ b/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_form.tsx
@@ -705,6 +705,7 @@ export const StepDefineForm: FC<Props> = React.memo(({ overrides = {}, onChange,
                       width="100%"
                       value={advancedEditorSourceConfig}
                       onChange={(d: string) => {
+                        setSearchString(undefined);
                         setAdvancedEditorSourceConfig(d);
 
                         // Disable the "Apply"-Button if the config hasn't changed.
diff --git a/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_summary.tsx b/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_summary.tsx
index 54cc1e8c071fa..f31514e67003b 100644
--- a/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_summary.tsx
+++ b/x-pack/plugins/transform/public/app/sections/create_transform/components/step_define/step_define_summary.tsx
@@ -17,7 +17,7 @@ import {
   EuiText,
 } from '@elastic/eui';
 
-import { getPivotQuery } from '../../../../common';
+import { getPivotQuery, isDefaultQuery, isMatchAllQuery } from '../../../../common';
 import { PivotPreview } from '../../../../components/pivot_preview';
 import { SearchItems } from '../../../../hooks/use_search_items';
 
@@ -60,24 +60,29 @@ export const StepDefineSummary: FC<Props> = ({
                     <span>{searchString}</span>
                   </EuiFormRow>
                 )}
-                {typeof searchString === 'undefined' && (
-                  <EuiFormRow
-                    label={i18n.translate('xpack.transform.stepDefineSummary.queryCodeBlockLabel', {
-                      defaultMessage: 'Query',
-                    })}
-                  >
-                    <EuiCodeBlock
-                      language="js"
-                      fontSize="s"
-                      paddingSize="s"
-                      color="light"
-                      overflowHeight={300}
-                      isCopyable
+                {typeof searchString === 'undefined' &&
+                  !isDefaultQuery(pivotQuery) &&
+                  !isMatchAllQuery(pivotQuery) && (
+                    <EuiFormRow
+                      label={i18n.translate(
+                        'xpack.transform.stepDefineSummary.queryCodeBlockLabel',
+                        {
+                          defaultMessage: 'Query',
+                        }
+                      )}
                     >
-                      {JSON.stringify(searchQuery, null, 2)}
-                    </EuiCodeBlock>
-                  </EuiFormRow>
-                )}
+                      <EuiCodeBlock
+                        language="js"
+                        fontSize="s"
+                        paddingSize="s"
+                        color="light"
+                        overflowHeight={300}
+                        isCopyable
+                      >
+                        {JSON.stringify(pivotQuery, null, 2)}
+                      </EuiCodeBlock>
+                    </EuiFormRow>
+                  )}
               </Fragment>
             )}