PHP-Google折线图“表没有列”-如何在JSON中获取行和列

我在将JSON数据解析到Google折线图时遇到问题。 我得到错误“表没有列”

我看了一下Google JSON，他们的是这样的：

{
  "cols": [
        {"id":"","label":"Topping","pattern":"","type":"string"},
        {"id":"","label":"Slices","pattern":"","type":"number"}
      ],
  "rows": [
        {"c":[{"v":"Mushrooms","f":null},{"v":3,"f":null}]},
        {"c":[{"v":"Onions","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Olives","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Zucchini","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Pepperoni","f":null},{"v":2,"f":null}]}
      ]
}

[{"user_id":"1","item1":"Jim","item2":"Smith","item3":"jim@tester.com"},{"user_id":"1","item1":"Joe","item2":"Tester","item3":"joe@tester.com"}]

到目前为止，我已经用PHP编写了这个JSON函数

function generateJSON($user_id){
    $sql="SELECT * FROM `csvupload` WHERE `user_id` = '$user_id'";
    $result=mysql_query($sql);
    $rows = array();
    while($r = mysql_fetch_assoc($result)) {
    $rows[] = $r;
}
print json_encode($rows);
}

输出如下：

{
  "cols": [
        {"id":"","label":"Topping","pattern":"","type":"string"},
        {"id":"","label":"Slices","pattern":"","type":"number"}
      ],
  "rows": [
        {"c":[{"v":"Mushrooms","f":null},{"v":3,"f":null}]},
        {"c":[{"v":"Onions","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Olives","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Zucchini","f":null},{"v":1,"f":null}]},
        {"c":[{"v":"Pepperoni","f":null},{"v":2,"f":null}]}
      ]
}

[{"user_id":"1","item1":"Jim","item2":"Smith","item3":"jim@tester.com"},{"user_id":"1","item1":"Joe","item2":"Tester","item3":"joe@tester.com"}]

有人知道我怎么能把行和列都用谷歌的吗？因为现在我只得到错误表没有列。感谢您的帮助！：