feat(Merge Node): Better pairedItem mapping in combineBySql operation if SELECT query (#13849)

Co-authored-by: Shireen Missi <94372015+ShireenMissi@users.noreply.github.com>

packages/nodes-base/nodes/Merge/test/v3/operations.test.ts

@@ -259,6 +259,142 @@ describe('Test MergeV3, combineBySql operation', () => {
 			country: 'PL',
 		});
 	});
+
+	it('should collect pairedItems data, if version >= 3.1 and SELECT query', async () => {
+		const nodeParameters: IDataObject = {
+			operation: 'combineBySql',
+			query: 'SELECT name FROM input1 LEFT JOIN input2 ON input1.id = input2.id',
+		};
+
+		const inputs = [
+			[
+				{
+					json: {
+						id: 1,
+						data: 'a',
+						name: 'Sam',
+					},
+					pairedItem: {
+						item: 0,
+						input: undefined,
+					},
+				},
+				{
+					json: {
+						id: 2,
+						data: 'b',
+						name: 'Dan',
+					},
+					pairedItem: {
+						item: 1,
+						input: undefined,
+					},
+				},
+				{
+					json: {
+						id: 3,
+						data: 'c',
+						name: 'Jon',
+					},
+					pairedItem: {
+						item: 2,
+						input: undefined,
+					},
+				},
+			],
+			[
+				{
+					json: {
+						id: 1,
+						data: 'aa',
+						country: 'PL',
+					},
+					pairedItem: {
+						item: 0,
+						input: 1,
+					},
+				},
+				{
+					json: {
+						id: 2,
+						data: 'bb',
+						country: 'FR',
+					},
+					pairedItem: {
+						item: 1,
+						input: 1,
+					},
+				},
+				{
+					json: {
+						id: 3,
+						data: 'cc',
+						country: 'UA',
+					},
+					pairedItem: {
+						item: 2,
+						input: 1,
+					},
+				},
+			],
+		];
+
+		const returnData = await mode.combineBySql.execute.call(
+			createMockExecuteFunction(nodeParameters, { ...node, typeVersion: 3.1 }),
+			inputs,
+		);
+
+		expect(returnData.length).toEqual(1);
+		expect(returnData).toEqual([
+			[
+				{
+					json: {
+						name: 'Sam',
+					},
+					pairedItem: [
+						{
+							item: 0,
+							input: undefined,
+						},
+						{
+							item: 0,
+							input: 1,
+						},
+					],
+				},
+				{
+					json: {
+						name: 'Dan',
+					},
+					pairedItem: [
+						{
+							item: 1,
+							input: undefined,
+						},
+						{
+							item: 1,
+							input: 1,
+						},
+					],
+				},
+				{
+					json: {
+						name: 'Jon',
+					},
+					pairedItem: [
+						{
+							item: 2,
+							input: undefined,
+						},
+						{
+							item: 2,
+							input: 1,
+						},
+					],
+				},
+			],
+		]);
+	});
 });
 
 describe('Test MergeV3, append operation', () => {

packages/nodes-base/nodes/Merge/test/v3/utils.test.ts

@@ -0,0 +1,92 @@
+import type { IDataObject, INodeExecutionData, IPairedItemData } from 'n8n-workflow';
+
+import { modifySelectQuery, rowToExecutionData } from '../../v3/helpers/utils';
+
+describe('rowToExecutionData', () => {
+	test('should return empty json and pairedItem when input is empty', () => {
+		const input: IDataObject = {};
+		const result = rowToExecutionData(input);
+		expect(result).toEqual({ json: {}, pairedItem: [] });
+	});
+
+	test('should separate json properties and pairedItem properties', () => {
+		const input: IDataObject = {
+			key1: 'value1',
+			key2: 42,
+			pairedItem1: { item: 0, input: undefined } as IPairedItemData,
+			pairedItem2: { item: 0, input: 1 } as IPairedItemData,
+		};
+
+		const expectedOutput: INodeExecutionData = {
+			json: { key1: 'value1', key2: 42 },
+			pairedItem: [
+				{ item: 0, input: undefined },
+				{ item: 0, input: 1 },
+			],
+		};
+
+		expect(rowToExecutionData(input)).toEqual(expectedOutput);
+	});
+
+	test('should ignore undefined pairedItem values', () => {
+		const input: IDataObject = {
+			key: 'value',
+			pairedItem1: { item: 0, input: undefined } as IPairedItemData,
+			pairedItem2: undefined,
+		};
+
+		const expectedOutput: INodeExecutionData = {
+			json: { key: 'value' },
+			pairedItem: [{ item: 0, input: undefined }],
+		};
+
+		expect(rowToExecutionData(input)).toEqual(expectedOutput);
+	});
+
+	test('should handle only json properties without pairedItem', () => {
+		const input: IDataObject = {
+			name: 'Alice',
+			age: 30,
+		};
+
+		const expectedOutput: INodeExecutionData = {
+			json: { name: 'Alice', age: 30 },
+			pairedItem: [],
+		};
+
+		expect(rowToExecutionData(input)).toEqual(expectedOutput);
+	});
+});
+
+describe('modifySelectQuery', () => {
+	test('should return the original query if no SELECT match is found', () => {
+		const query = 'UPDATE table SET column = 1';
+		expect(modifySelectQuery(query, 2)).toBe(query);
+	});
+
+	test('should return the original query if SELECT * is used', () => {
+		const query = 'SELECT * FROM input1';
+		expect(modifySelectQuery(query, 2)).toBe(query);
+	});
+
+	test('should append pairedItem columns when input tables exist', () => {
+		const query = 'SELECT column1, column2 FROM input1 WHERE input1.id = table.id';
+		const modifiedQuery = modifySelectQuery(query, 2);
+		expect(modifiedQuery).toBe(
+			'SELECT column1, column2, input1.pairedItem AS pairedItem1 FROM input1 WHERE input1.id = table.id',
+		);
+	});
+
+	test('should handle multiple input tables correctly', () => {
+		const query = 'SELECT column1 FROM input1 LEFT JOIN input2 ON input1.name = input2.name';
+		const modifiedQuery = modifySelectQuery(query, 2);
+		expect(modifiedQuery).toBe(
+			'SELECT column1, input1.pairedItem AS pairedItem1, input2.pairedItem AS pairedItem2 FROM input1 LEFT JOIN input2 ON input1.name = input2.name',
+		);
+	});
+
+	test('should not modify query if no input tables are found', () => {
+		const query = 'SELECT column1 FROM table';
+		expect(modifySelectQuery(query, 2)).toBe(query);
+	});
+});