Fusion Tables API Visualization中的柱形图不是动态的

Question

我的柱形图不是动态的。当我选择县时，它没有改变。我使用与融合表API高级可视化中给出的相同的代码。可能是什么问题？

 function drawVisualization(County) {
    google.visualization.drawChart({
      containerId: "visualization",
      dataSourceUrl: "http://www.google.com/fusiontables/gvizdata?tq=",
      query: "SELECT Environment,'BoyPupils','GirlPupils'" +
          "FROM 1eC4sIAgVXfFj01mOM2cDiyW2nly7TcFeIXj1G3s WHERE County = '" + County + "'",
      chartType: "ColumnChart",
      options: {
        title: County,
        height: 400,
        width: 400
      }
    });
  }