<th class="col-md-3"><a href="" ng-click="desc('2',la=!la)">单价</a></th>
 <th class="col-md-3"><a href="" ng-click="desc('3',la=!la)">销售金额</a></th>
 <th class="col-md-1"><a href="" ng-click="desc('4',la=!la)">销售数量</a></th>

//开始默认为totalnum字段 按照降序排列

$scope.foodsale =ret.sort(function ( x,y )
    {
     return y.totalnum - x.totalnum;//这样表示 按照ret【表示接收返回数组】里面的totalnum字段 按照降序排列 反之 return x.totalnum - y.totalnum; 为升序
})
　　

 $scope.desc= function (fla,bol) {
   if(fla=="4"){
    if(bol==false){
     
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
     {
      return y.totalnum - x.totalnum;
     })
    }else{
     console.log("bbb")
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
     {
      return x.totalnum - y.totalnum;
     })
    }
   }else if(fla=="3"){//totalmoney
    if(bol==false){
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
     {
      return y.totalmoney - x.totalmoney;
     })
    }else{
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
      {
       return x.totalmoney - y.totalmoney;
      }
     )
    }
   }else if(fla=="2"){//price
    if(bol==false){
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
     {
      return y.price - x.price;
     })
    }else{
     $scope.foodsale =$scope.foodsale.sort(function ( x,y )
      {
       return x.price - y.price;
      }
     )
    }
   }