fix(h-grid): select proper return field when there is single child entity

Author: teodosiah

projects/igniteui-angular/src/lib/grids/grid/grid-filtering-advanced.spec.ts

@@ -1593,11 +1593,17 @@ describe('IgxGrid - Advanced Filtering #grid - ', () => {
             tick(100);
             fix.detectChanges();
 
+            // When there is one entity, it should be selected by default
             const entityInputGroup = QueryBuilderFunctions.getQueryBuilderEntitySelect(fix, 1).querySelector('input');
             expect(entityInputGroup.value).toBe('childData');
 
             const fieldInputGroup = QueryBuilderFunctions.getQueryBuilderFieldsCombo(fix, 1).querySelector('input');
             expect(fieldInputGroup.value).toBe('ID');
+
+            // Click the initial 'Add Condition' button.
+            QueryBuilderFunctions.clickQueryBuilderInitialAddConditionBtn(fix, 0);
+            tick(100);
+            fix.detectChanges();
             // Populate edit inputs on level 1.
             QueryBuilderFunctions.selectColumnInEditModeExpression(fix, 0, 1); // Select 'ID' column.
             QueryBuilderFunctions.selectOperatorInEditModeExpression(fix, 0, 1); // Select 'Contains' operator. 
@@ -1625,13 +1631,14 @@ describe('IgxGrid - Advanced Filtering #grid - ', () => {
         it(`Should have correct return fields in the child query when there are multiple child entities.`, fakeAsync(() => {
             const fixture = TestBed.createComponent(IgxHierarchicalGridExportComponent);
             const hierarchicalGrid = fixture.componentInstance.hGrid;
+            fixture.componentInstance.shouldDisplayArtist = true;
             hierarchicalGrid.allowAdvancedFiltering = true;
             fixture.detectChanges();
 
             hierarchicalGrid.openAdvancedFilteringDialog();
             fixture.detectChanges();
 
-             // Click the initial 'Add Condition' button.
+            // Click the initial 'Add Condition' button.
             QueryBuilderFunctions.clickQueryBuilderInitialAddConditionBtn(fixture, 0);
             tick(100);
             fixture.detectChanges();

projects/igniteui-angular/src/lib/query-builder/query-builder-tree.component.ts

@@ -563,6 +563,9 @@ export class IgxQueryBuilderTreeComponent implements AfterViewInit, OnDestroy {
 
         if (this.isAdvancedFiltering() && this.entities?.length === 1) {
             this.selectedEntity = this.entities[0].name;
+            if (this._selectedEntity.fields.find(f => f.field === this.expectedReturnField)) {
+                this._selectedReturnFields = [this.expectedReturnField];
+            }
         }
 
         // Trigger additional change detection cycle

projects/igniteui-angular/src/lib/test-utils/hierarchical-grid-components.spec.ts

@@ -484,7 +484,9 @@ export class IgxHierGridExternalAdvancedFilteringComponent extends IgxHierarchic
             <igx-column field="LaunchDate" header="Launch Date" [dataType]="'date'"></igx-column>
             <igx-column field="BillboardReview" header="Billboard Review"></igx-column>
             <igx-column field="USBillboard200" header="US Billboard 200"></igx-column>
-            <igx-column field="Artist"></igx-column>
+            @if(shouldDisplayArtist) {
+                <igx-column field="Artist"></igx-column>
+            }
             <igx-row-island [key]="'Songs'" [allowFiltering]='true' [filterMode]="'excelStyleFilter'" [autoGenerate]="false">
                 <igx-column field="Number" header="No."></igx-column>
                 <igx-column field="Title"></igx-column>
@@ -511,6 +513,7 @@ export class IgxHierGridExternalAdvancedFilteringComponent extends IgxHierarchic
 export class IgxHierarchicalGridExportComponent {
     @ViewChild('hierarchicalGrid', { read: IgxHierarchicalGridComponent, static: true }) public hGrid: IgxHierarchicalGridComponent;
     public data = SampleTestData.hierarchicalGridExportData();
+    public shouldDisplayArtist = false;
 }