Question

我试图显示一条错误消息，当数据库（mysql）的结果是0时这将是一条错误消息。

下面的代码我试图使用ajax来获取SQL结果，当它返回0时会显示错误。

$.ajax({
  type: "POST",
  url: "charts/prod.php?year=" + $("#selectyear").val() + "&month=" + $("#selectmonth").val(),
  dataType: "json", // serializes the form's elements.
  success: function (result) { 
  var chart = c3.generate({
       bindto: '#piepie',
       data: result.value,
       color: { 
         pattern: ['#f35213', '#f1af4c'] },
         pie: { title: "Productivity", }
     });

  },
  error: function() {

        if (result.percentage==undefined){ 
  alert ('Data are not ready yet!!');  
} else {
alert(result.percentage);
}
}   
});

Answer 1

$.ajax({
      type: "POST",
      url: "charts/prod.php?year=" + $("#selectyear").val() + "&month=" + $("#selectmonth").val(),
      dataType: "json", // serializes the form's elements.
      success: function (result) { 
        
        if (result.value == "0"){
          alert ('ERROR!!');  
        } else {
        
         var chart = c3.generate({
           bindto: '#piepie',
           data: result.value,
           color: { 
             pattern: ['#f35213', '#f1af4c'] },
             pie: { title: "Productivity", }
         });
        
        }
      },
      error: function() {
          alert ('Error');  
      } 
});

试试这个

Answer 2

    if (result.percentage.length==0){ // THIS IS WHAT YOU NEED.
      alert ('ERROR!!');  
    } else {
     // YOUR CODE GOES HERE.

    }

正如您所评论的那样，结果为“{”百分比“：[]}'。因此，您将百分比属性作为长度为0的数组。因此，您只需要测试它。

Answer 3

试试这个！

if ((typeof result !== " undefined") && (result !== null) && (result == 0)){
    alert("YourErrorMessageHere"); 
}

如果ajax从sql

3 个答案: