我正在用蟒蛇和烧瓶购物车 . 我希望当用户点击某个项目上的订单按钮时，它们会被重定向到/ cart / add / route，其中运行SQL语句以从用户表中检索用户名，项目名称和来自allfood表的价格等数据基于项目ID在来自delivery_address表的URL和地址中传递 . 收集此信息后，它也会被添加到shopping_cart表中，暂时保存，直到我找到下一步 . 我遇到了SQL问题，我希望有人可以纠正它，因为它给了我一个错误 .

"INSERT INTO shopping_cart_tbl VALUES (username, address, item, cost) \
        SELECT user.username, addr.address, food.item_, food.cost \
        FROM register_tbl AS user FULL JOIN delivery_addresses_tbl AS addr FULL JOIN allfood_tbl AS food \
        ON user.username = addr.username AND food.id=%s"

为了知道我是否可以通过任何建议改进我的代码，我将发布路由的代码

@app.route('/cart/add/<item_id>', methods=['POST', 'GET'])
 def sadd_to_cart(item_id):
    # do a cross join of the three tables maybe to retrieve the necessarinformation
    if 'userkey' in session:
        con = pymysql.connect("localhost", "root", "", "sampledb")
        cursor_full_join = con.cursor()
        sql="INSERT INTO shopping_cart_tbl VALUES (username, address, item, cost) \
            SELECT user.username, addr.address, food.item_, food.cost \
            FROM register_tbl AS user FULL JOIN delivery_addresses_tbl AS addr FULL JOIN allfood_tbl AS food \
            ON user.username = addr.username AND food.id=%s" 

        cursor_full_join.execute(sql, item_id)

        return render_template('homepage.html')

    elif 'userkey' not in session:
        return redirect('/login')
    else:
        return redirect('/login')

我很感激帮助 . 编辑：我删除了不必要的引号 . 抱歉 . 我出于某种原因没有注意到它们

python mysql flask