php – 按字段分组在MongoDB中不起作用

我正在尝试计算我的数据库中所有记录的总和,我需要避免重复.我写了这段代码来对记录进行分组,但它对我不起作用.

$pipeline = [
    ['$match' =>
            $criteria->getCondition()],['$group' => 
            ['_id' => '$order_id','total' => ['$sum' => '$'.$column]]]
];

$this->getDbConnection()->aggregate('ticket_cache',$pipeline);

测试要求：

db.getCollection('ticket_cache').aggregate(
{
"$match":
    {"event_id":64}
},{
    "$group" : 
        {"_id":"$order_id","total": {"$sum":"$payment_amount"}}
})

结果：

/* 1 */
{
    "result" : [ 
        {
            "_id" : NumberLong(7002),"total" : 9000.0000000000000000
        }
    ],"ok" : 1.0000000000000000
}

db中的数据：

/* 1 */
{
    "result" : [ 
        {
            "_id" : ObjectId("553f8b4fbfabe2772f8b4f51"),"event_id" : NumberLong(64),"ticket_id" : NumberLong(8563),"ticket_code" : NumberLong(22062299),"ticket_type_id" : NumberLong(391),"ticket_created" : NumberLong(1430227620),"ticket_deleted" : NumberLong(0),"ticket_user_id" : NumberLong(2),"ticket_used" : NumberLong(0),"order_id" : NumberLong(7002),"order_code" : NumberLong(517005),"order_created" : NumberLong(1430227620),"order_deleted" : NumberLong(0),"order_sales_pipeline" : NumberLong(18),"order_invoice_id" : NumberLong(4202),"order_invoice_amount" : 3000.0000000000000000,"order_invoice_created" : NumberLong(1430227641),"order_invoice_deleted" : NumberLong(0),"order_invoice_code" : NumberLong(420155),"payment_id" : NumberLong(4365),"payment_amount" : 3000.0000000000000000,"payment_currency" : NumberLong(4),"payment_author_id" : NumberLong(1),"payment_type_id" : NumberLong(27),"payment_created" : NumberLong(1430227641),"payment_deleted" : NumberLong(0),"create_time" : ISODate("2015-04-28T13:29:51.328Z")
        },{
            "_id" : ObjectId("553f8b4fbfabe2772f8b4f4f"),"ticket_id" : NumberLong(8561),"ticket_code" : NumberLong(49287433),"create_time" : ISODate("2015-04-28T13:29:51.316Z")
        },{
            "_id" : ObjectId("553f8b4fbfabe2772f8b4f50"),"ticket_id" : NumberLong(8562),"ticket_code" : NumberLong(24016753),"create_time" : ISODate("2015-04-28T13:29:51.326Z")
        }
    ],"ok" : 1.0000000000000000
}

我哪里做错了？

解决方法

你可以尝试使用以下查询.它假定付款金额将始终相同.看看addToSet http://docs.mongodb.org/manual/reference/operator/update/addToSet/.

db.getCollection('ticket_cache').aggregate( 
{ "$match": {"event_id":64} },{ "$group" :
     {"_id":"$order_id","total": {"$addToSet":"$payment_amount"}}
},{"$unwind": "$total"},{"$group": {"_id": "null","totalOdr": {"$sum": "$total"}}}
)