How to multiply 2 column data by passing a product id in SQLite?

I need to multiply value of 2 column in which is in my sqlite table. I have done this. But I missed to pass a specific product id to do multiplication.I used following code to multiply to column.

public int getMultiply() {
    Cursor cursor = db.rawQuery("SELECT " + DbHelper.CART_QUANTITY + " * " + DbHelper.CART_PRICE + " AS result FROM " + DbHelper.CART_TABLE, null);

    if (cursor.moveToFirst()) {
        Log.w("result", cursor.getDouble(0) + "");
        return (int) cursor.getDouble(0);
    }
    return 0;
}

Now I need to correct my calculation by passing Product Id.How to multiply 2 column by passing parameter?

public int getMultiply(String PID) {..........return 0;}