Question

我需要帮助为MongoDB中的以下集合编写查询。

我需要计算总数。产品[“data”包含所有活动产品组中的产品]
群组处于活动状态是status = 1

以下是ProductGroups的示例层次结构：

>ProductGroup1
 - Group1
   - product11
   - product12
     ...
 - Group2 
   - product21
>ProductGroup22
 - Group21
   - product211
   - product212
     ...
 - Group22
   - product221
...

以下是1个产品组的示例。可以有许多产品组。样本集：

{"_id":ObjectId("abcd"), "_class":"PGroup", 
"name":"test", 
"status"=1, 
"groups": [
"name":"group1","data": [{"url":"urlofproduct1", "name":"product1"}, {"url":"urlofproduct2", "name":"product2"}, ...],
"name":"group2","data": [{"url":"urlofproduct1", "name":"product1"}, {"url":"urlofproduct2", "name":"product2"}, ...],
...
"name":"group10","data": [{"url":"urlofproduct1", "name":"product1"}, {"url":"urlofproduct2", "name":"product2"}, ...],
]}

Answer 1

重新构建您的数据，如下所示：

internal class SimpleDispatcherContext : SynchronizationContext
{
    private readonly Dispatcher _dispatcher;
    private readonly DispatcherPriority _priority;
    public SimpleDispatcherContext(Dispatcher dispatcher, DispatcherPriority priority = DispatcherPriority.Normal)
    {
        _dispatcher = dispatcher;
        _priority = priority;
    }

    public override void Post(SendOrPostCallback d, object state) {
        var op = this._dispatcher.BeginInvoke(_priority, d, state);
        // here, default sync context just does nothing
        if (op.Status == DispatcherOperationStatus.Aborted)
            throw new OperationCanceledException("Dispatcher has shut down");
    }

    public override void Send(SendOrPostCallback d, object state) {
        _dispatcher.Invoke(d, _priority, state);
    }
}

private async Task LoadData()
{
    SynchronizationContext.SetSynchronizationContext(new SimpleDispatcherContext(Dispatcher));
    // Fetch data
    var data = await FetchData();

    // Display data
    // ...
}

此外，我希望您尝试查找所有产品组中所有产品的总数。试试这个问题，如果这就是你要找的东西：

/* 1 */
{
"_id" : "abcd",
"_class" : "PGroup",
"name" : "test",
"status" : 1,
"groups" : [ 
    {
        "name" : "group1",
        "data" : [ 
            {
                "url" : "urlofproduct1",
                "name" : "product1"
            }, 
            {
                "url" : "urlofproduct2",
                "name" : "product2"
            }
        ]
    }, 
    {
        "name" : "group2",
        "data" : [ 
            {
                "url" : "urlofproduct1",
                "name" : "product1"
            }, 
            {
                "url" : "urlofproduct2",
                "name" : "product2"
            }
        ]
    }, 
    {
        "name" : "group10",
        "data" : [ 
            {
                "url" : "urlofproduct1",
                "name" : "product1"
            }, 
            {
                "url" : "urlofproduct2",
                "name" : "product2"
            }
        ]
    }
 ]
}

db.collection.aggregate([ {$match:{status:1}}, {$unwind:"$groups"}, {$unwind:"$groups.data"}, {$group:{_id:null,count:{$sum:1}}} ])将为您提供所有群组的产品总数。如果您需要查找每个产品组下的总产品数量，则查询会有所不同，只需在count上$group，如果这符合您的要求。希望这能回答你的问题。

编写复杂查询以在MongoDB中计数

1 个答案: