I have done similar modification for a client. You will need to modify the following scripts Report.php, core.js, and sales report view file themes/default/admin/view/reports/sales.php.

In Report controller app/controllers/admin/Report.php modify getSalesReport method by adding product_code to the concatenated item_nane alias.

In Core js script themes\default\admin\assets\js\core.js you will need to create a replicate of pqFormat method/function as other scripts depend on the function.

Then modify the replicated function to include value for product code in the concatenated variable item_nane alias. See the example below.

	function pqcFormat(x) {
		if (x != null) {
			var d = '',
				pqc = x.split('___');
			for (index = 0; index < pqc.length; ++index) {
				var pq = pqc[index];
				var v = pq.split('__');
				d += v[0] + ' (Qty: ' + formatQuantity2(v[1]) + ') (Code: ' + v[2] + ')<br>';
			}
			return d;
		} else {
			return '';
		}
	}

Hello,

There is no option to add item code as you want. You will need to modify the item code to get desired results.

Thank you