Add test for UNION with ORDER BY to confirm #671 (#2277)

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: mathiasrw <[email protected]>

Author: Copilot

test/test671.js

@@ -0,0 +1,98 @@
+if (typeof exports === 'object') {
+	var assert = require('assert');
+	var alasql = require('..');
+}
+
+describe('Test 671 - UNION with ORDER BY', function () {
+	const test = '671';
+
+	before(function () {
+		alasql('create database test' + test);
+		alasql('use test' + test);
+	});
+
+	after(function () {
+		alasql('drop database test' + test);
+	});
+
+	it('A) UNION ALL with ORDER BY on alias', function () {
+		var projects = [
+			{projectID: 1, Date1: '2023-01-01', Date2: '2023-02-01'},
+			{projectID: 2, Date1: '2023-03-01', Date2: '2023-01-15'},
+			{projectID: 3, Date1: '2023-02-01', Date2: '2023-04-01'},
+		];
+
+		var res = alasql(
+			'SELECT projectID, Date1 as theDate FROM $0 UNION ALL SELECT projectID, Date2 as theDate FROM $0 ORDER BY theDate',
+			[projects]
+		);
+
+		assert.equal(res.length, 6);
+		// Verify correct ascending order
+		assert.equal(res[0].theDate, '2023-01-01');
+		assert.equal(res[1].theDate, '2023-01-15');
+		assert.equal(res[2].theDate, '2023-02-01');
+		assert.equal(res[3].theDate, '2023-02-01');
+		assert.equal(res[4].theDate, '2023-03-01');
+		assert.equal(res[5].theDate, '2023-04-01');
+	});
+
+	it('B) UNION ALL with ORDER BY DESC', function () {
+		var projects = [
+			{projectID: 1, Date1: '2023-01-01', Date2: '2023-02-01'},
+			{projectID: 2, Date1: '2023-03-01', Date2: '2023-01-15'},
+		];
+
+		var res = alasql(
+			'SELECT projectID, Date1 as theDate FROM $0 UNION ALL SELECT projectID, Date2 as theDate FROM $0 ORDER BY theDate DESC',
+			[projects]
+		);
+
+		assert.equal(res.length, 4);
+		// Verify correct descending order
+		assert.equal(res[0].theDate, '2023-03-01');
+		assert.equal(res[1].theDate, '2023-02-01');
+		assert.equal(res[2].theDate, '2023-01-15');
+		assert.equal(res[3].theDate, '2023-01-01');
+	});
+
+	it('C) UNION with ORDER BY (removes duplicates)', function () {
+		var data = [
+			{a: 1, b: 'x'},
+			{a: 2, b: 'y'},
+			{a: 3, b: 'z'},
+		];
+
+		var res = alasql(
+			'SELECT a FROM $0 WHERE a < 3 UNION SELECT a FROM $0 WHERE a > 1 ORDER BY a DESC',
+			[data]
+		);
+
+		assert.equal(res.length, 3);
+		assert.equal(res[0].a, 3);
+		assert.equal(res[1].a, 2);
+		assert.equal(res[2].a, 1);
+	});
+
+	it('D) UNION ALL with multiple ? parameters', function () {
+		var data1 = [
+			{id: 1, value: 'a'},
+			{id: 2, value: 'b'},
+		];
+		var data2 = [
+			{id: 3, value: 'c'},
+			{id: 4, value: 'd'},
+		];
+
+		var res = alasql('SELECT id, value FROM ? UNION ALL SELECT id, value FROM ? ORDER BY id', [
+			data1,
+			data2,
+		]);
+
+		assert.equal(res.length, 4);
+		assert.equal(res[0].id, 1);
+		assert.equal(res[1].id, 2);
+		assert.equal(res[2].id, 3);
+		assert.equal(res[3].id, 4);
+	});
+});