Google图表“数据列”中轴#0的引号错误不能为字符串类型

我知道这个问题已经被问过很多次了，但是我还没有真正为我的代码找到一个解决方案。我选择供应商和年份，我想显示所有产品的列表。

经过多次测试，我发现我的代码对所有供应商都有效，除了供应商的名字带有引号和重音。

这是我的错误:

"轴#0的数据列不能为字符串类型"

<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
    google.load("visualization", "1", {
        packages: ["corechart"]
    });
    google.setOnLoadCallback(drawChart);
    function drawChart() {
        var data = google.visualization.arrayToDataTable([
            ['Month', 'Product', 'Items'],
            <?php foreach ($my_data as $a => $b): ?> ['<?php echo $month[$b['
                month ']]?>', <?php echo $b['product'] ?>, <?php echo $b['items'] ?>,
            ],
            <?php endforeach; ?>
        ]);
        var options = {
            title: 'supplier',
            hAxis: {
                title: 'product supplier',
                titleTextStyle: {
                    color: '#333'
                }
            },
            vAxis: {
                minValue: 0
            }
        };
        var chart = new google.visualization.AreaChart(document.getElementById('chart_div'));
        chart.draw(data, options);
    }
</script>

这是我的查询:

 if(isset($_POST['$value1'] ))
    {
    $month = array('','January','February ','March','April','May','June','July','August','September','October','November','December');
    $value1 = $_POST['$value1'] ;
    $value2 = $_POST['$value1'] ;
    $sql="  SELECT
                name,
                count(items),
                MONTH(created_at) as month,
                YEAR(created_at) as year,
                sum(product) as product
            FROM `supplier_product`
            where 
                name = '".$value1."' and YEAR(date.created_at) = '".$value2."'
                GROUP BY name,month
                ORDER BY month ASC
        ";

这是我的代码PHP:

            <label for="supplier"> Select name : </label>
                                        <select name = "value1" id="sup">
                                            <?php
                                            $sql = "SELECT name FROM supplier_product";
                                            $req = $mydatabase->prepare($sql);
                                            $req->execute();
                                            $data = $req->fetchAll(PDO::FETCH_ASSOC);
                                            foreach ($data as $a => $b):
                                            ?>
                                            <option value="<?php echo utf8_encode($v['name']); ?>"><?php echo utf8_encode($v['name']); ?></option>
                                             <?php
                                            endforeach;
                                                ?>
                                        </select>
                                        <select name= "value2">
                                            <option value="2015">2015</option>
                                            <option value="2014">2014</option>
                                            <option value="2014">2013</option>
                                            <option value="2014">2012</option>
                                            <option value="2014">2011</option>
                                            <option value="2014">2010</option>
                                            <option value="2014">2019</option>
                                        </select>

请帮帮我。非常感谢您的帮助。