diff --git a/src/70insert.js b/src/70insert.js
index 149dfd33bf..af0858748a 100755
--- a/src/70insert.js
+++ b/src/70insert.js
@@ -243,7 +243,10 @@ yy.Insert.prototype.compile = function (databaseid) {
 			return statement;
 		} else {
 			//			console.log(224,table.defaultfns);
-			var defaultfns = 'return alasql.utils.extend(r,{' + table.defaultfns + '})';
+			var defaultfns =
+				'var defaults={' +
+				table.defaultfns +
+				'};for(var key in defaults){if(!(key in r)){r[key]=defaults[key]}}return r';
 			var defaultfn = new Function('r,db,params,alasql', defaultfns);
 			var insertfn = function (db, params, alasql) {
 				var res = selectfn(params).data;
diff --git a/test/test1484.js b/test/test1484.js
new file mode 100644
index 0000000000..7cd6c325f2
--- /dev/null
+++ b/test/test1484.js
@@ -0,0 +1,189 @@
+if (typeof exports === 'object') {
+	var assert = require('assert');
+	var alasql = require('..');
+}
+
+describe('Test 1484 - INSERT FROM parameter with defaults', function () {
+	it('1. INSERT INTO table SELECT * FROM ? with data array', () => {
+		// Create a new database like in the issue
+		var inmemDB = new alasql.Database('test_insert_db');
+
+		// Create table
+		var query =
+			"CREATE TABLE IF NOT EXISTS [BCPartners] (RecordNum INTEGER PRIMARY KEY AUTOINCREMENT, [TABLE_NAME] TEXT DEFAULT '', [BC] TEXT DEFAULT '')";
+		inmemDB.exec(query);
+
+		// Prepare test data
+		var data = [
+			{TABLE_NAME: 'Table1', BC: 'BC1'},
+			{TABLE_NAME: 'Table2', BC: 'BC2'},
+			{TABLE_NAME: 'Table3', BC: 'BC3'},
+		];
+
+		// Insert data
+		inmemDB.exec('INSERT INTO [BCPartners] SELECT * FROM ?', [data]);
+
+		// Verify data was inserted correctly
+		var result = inmemDB.exec('SELECT * FROM [BCPartners]');
+
+		var expected = [
+			{RecordNum: 1, TABLE_NAME: 'Table1', BC: 'BC1'},
+			{RecordNum: 2, TABLE_NAME: 'Table2', BC: 'BC2'},
+			{RecordNum: 3, TABLE_NAME: 'Table3', BC: 'BC3'},
+		];
+		assert.deepEqual(result, expected);
+
+		// Clean up
+		alasql('DROP DATABASE test_insert_db');
+	});
+
+	it('2. INSERT INTO table SELECT * FROM ? using default database', () => {
+		// Test with default database (alasql)
+		alasql('DROP TABLE IF EXISTS BCPartners');
+		alasql(
+			"CREATE TABLE BCPartners (RecordNum INTEGER PRIMARY KEY AUTOINCREMENT, TABLE_NAME TEXT DEFAULT '', BC TEXT DEFAULT '')"
+		);
+
+		// Prepare test data
+		var data = [
+			{TABLE_NAME: 'Table1', BC: 'BC1'},
+			{TABLE_NAME: 'Table2', BC: 'BC2'},
+		];
+
+		// Insert data
+		alasql('INSERT INTO BCPartners SELECT * FROM ?', [data]);
+
+		// Verify data was inserted correctly
+		var result = alasql('SELECT * FROM BCPartners');
+
+		var expected = [
+			{RecordNum: 1, TABLE_NAME: 'Table1', BC: 'BC1'},
+			{RecordNum: 2, TABLE_NAME: 'Table2', BC: 'BC2'},
+		];
+		assert.deepEqual(result, expected);
+
+		// Clean up
+		alasql('DROP TABLE BCPartners');
+	});
+
+	it('3. INSERT with partial columns - defaults should apply for missing columns', () => {
+		alasql('DROP TABLE IF EXISTS TestDefaults');
+		alasql(
+			'CREATE TABLE TestDefaults (id INT, name TEXT DEFAULT "NoName", status TEXT DEFAULT "Active")'
+		);
+
+		// Insert data with only id and name
+		var data = [
+			{id: 1, name: 'Item1'},
+			{id: 2, name: 'Item2'},
+		];
+		alasql('INSERT INTO TestDefaults SELECT * FROM ?', [data]);
+
+		var result = alasql('SELECT * FROM TestDefaults');
+
+		// status should have default value
+		var expected = [
+			{id: 1, name: 'Item1', status: 'Active'},
+			{id: 2, name: 'Item2', status: 'Active'},
+		];
+		assert.deepEqual(result, expected);
+
+		alasql('DROP TABLE TestDefaults');
+	});
+
+	it('4. INSERT with empty source columns should preserve empty values not defaults', () => {
+		alasql('DROP TABLE IF EXISTS TestEmpty');
+		alasql('CREATE TABLE TestEmpty (id INT, val TEXT DEFAULT "DefaultValue")');
+
+		// Insert data with empty string (not undefined/missing)
+		var data = [
+			{id: 1, val: ''},
+			{id: 2, val: ''},
+		];
+		alasql('INSERT INTO TestEmpty SELECT * FROM ?', [data]);
+
+		var result = alasql('SELECT * FROM TestEmpty');
+
+		// Empty strings should be preserved, not replaced with defaults
+		var expected = [
+			{id: 1, val: ''},
+			{id: 2, val: ''},
+		];
+		assert.deepEqual(result, expected);
+
+		alasql('DROP TABLE TestEmpty');
+	});
+
+	it('5. INSERT from subquery with defaults', () => {
+		alasql('DROP TABLE IF EXISTS Source');
+		alasql('DROP TABLE IF EXISTS TargetTable');
+		alasql('CREATE TABLE Source (id INT, name TEXT)');
+		alasql('CREATE TABLE TargetTable (id INT, name TEXT, timestamp TEXT DEFAULT "2025")');
+
+		// Insert source data
+		alasql('INSERT INTO Source VALUES (1, "A"), (2, "B")');
+
+		// Insert from source to target - timestamp should get default
+		alasql('INSERT INTO TargetTable SELECT * FROM Source');
+
+		var result = alasql('SELECT * FROM TargetTable');
+
+		var expected = [
+			{id: 1, name: 'A', timestamp: '2025'},
+			{id: 2, name: 'B', timestamp: '2025'},
+		];
+		assert.deepEqual(result, expected);
+
+		alasql('DROP TABLE Source');
+		alasql('DROP TABLE TargetTable');
+	});
+
+	it('6. INSERT with mixed present and missing columns', () => {
+		alasql('DROP TABLE IF EXISTS MixedTest');
+		alasql(
+			'CREATE TABLE MixedTest (a INT, b TEXT DEFAULT "B_default", c TEXT DEFAULT "C_default", d TEXT DEFAULT "D_default")'
+		);
+
+		// Some records have different columns
+		var data = [
+			{a: 1, b: 'B1', c: 'C1'}, // missing d
+			{a: 2, c: 'C2', d: 'D2'}, // missing b
+			{a: 3, b: 'B3', d: 'D3'}, // missing c
+		];
+		alasql('INSERT INTO MixedTest SELECT * FROM ?', [data]);
+
+		var result = alasql('SELECT * FROM MixedTest');
+
+		var expected = [
+			{a: 1, b: 'B1', c: 'C1', d: 'D_default'},
+			{a: 2, b: 'B_default', c: 'C2', d: 'D2'},
+			{a: 3, b: 'B3', c: 'C_default', d: 'D3'},
+		];
+		assert.deepEqual(result, expected);
+
+		alasql('DROP TABLE MixedTest');
+	});
+
+	it('7. INSERT with undefined values should preserve undefined not apply defaults', () => {
+		alasql('DROP TABLE IF EXISTS UndefinedTest');
+		alasql('CREATE TABLE UndefinedTest (id INT, val TEXT DEFAULT "DefaultVal")');
+
+		// Explicitly set val to undefined
+		var data = [
+			{id: 1, val: undefined},
+			{id: 2, val: null},
+		];
+		alasql('INSERT INTO UndefinedTest SELECT * FROM ?', [data]);
+
+		var result = alasql('SELECT * FROM UndefinedTest');
+
+		// undefined and null should be preserved
+		var expected = [
+			{id: 1, val: undefined},
+			{id: 2, val: null},
+		];
+		assert.deepEqual(result, expected);
+
+		alasql('DROP TABLE UndefinedTest');
+	});
+});