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[英]MongoDb/PHP, can't get grouping to work right with aggregate framework
[英]I can not get data to aggregate It. PHP + mongoDB
它像我需要的那樣工作:
$out = $collection->aggregate(
array(
'$match' => array('type' => 'chair')
),
array(
'$project' => array(
'chairtype' => 1,
'mijczjeqeo'=>1
)
),
array(
'$group' => array(
'_id' => '$chairtype',
'MIDDLE_mijczjeqeo' => array('$avg' => '$mijczjeqeo'),
'SUMMA__mijczjeqeo' => array('$sum' => '$mijczjeqeo')
)
)
);
my_dump($out);
但是我需要從同一文檔中的數組中獲取用於聚合的真實數據:版本[0] [內容] [mijczjeqeo]
請更正我的腳本。 這是行不通的:
$out = $collection->aggregate(
array(
'$match' => array('type' => 'chair')
),
array(
'$project' => array(
'chairtype' => 1,
'versions.0.content.mijczjeqeo'=>1
)
),
array(
'$group' => array(
'_id' => '$chairtype',
'MIDDLEmijczjeqeo' => array('$avg' => '$versions.0.content.mijczjeqeo'),
'SUMMAmijczjeqeo' => array('$sum' => '$versions[0]["content"]["mijczjeqeo"]')
)
)
);
沒有一種方法不起作用:
'MIDDLEmijczjeqeo'=>數組('$ avg'=>'$ versions.0.content.mijczjeqeo')
'SUMMAmijczjeqeo'=>數組('$ sum'=>'$ versions [0] [“ content”] [“ mijczjeqeo”]')
我認為問題在.0附近。
我嘗試在mongo控制台中執行此操作...
db.documents.aggregate({$match:{'type':'chair'}},{$project:{'chairtype': 1, 'mijczjeqeo':1}},{$group:{'_id':'$chairtype','MID':{$avg:'$mijczjeqeo'}}})
{
"result" : [
{
"_id" : "T",
"MID" : 6.615384615384615
},
{
"_id" : "G",
"MID" : 8.310344827586206
},
{
"_id" : "E",
"MID" : 6.9523809523809526
}
],
"ok" : 1
}
db.documents.aggregate({$match:{'type':'chair'}},{$project:{'chairtype': 1, 'versions.0.content.mijczjeqeo':1}},{$group:{'_id':'$chairtype','MID':{$avg:'$versions.0.content.mijczjeqeo'}}})
{
"result" : [
{
"_id" : "T",
"MID" : 0
},
{
"_id" : "G",
"MID" : 0
},
{
"_id" : "E",
"MID" : 0
}
],
"ok" : 1
}
好吧,您不能在聚合管道中進行此類投影。 如果要對聚合語句中的數組元素進行操作,則首先需要$unwind
該數組,然后$match
所需的元素,或者根據情況選擇使用額外的$group
階段選擇$first
項。
您的問題沒有顯示文檔的結構,因此我將僅使用一個示例作為“椅子”集合:
{
"_id": 1,
"type": "chair",
"chairtype": "A",
"versions": [
{
"revision": 1,
"content": {
"name": "ABC",
"value": 10
}
},
{
"revision": 2,
"content": {
"name": "BBB",
"value": 15
}
}
]
}
{
"_id": 2,
"type": "chair",
"chairtype": "A",
"versions": [
{
"revision": 1,
"content": {
"name": "CCC",
"value": 20
}
},
{
"revision": 2,
"content": {
"name": "BAB",
"value": 12
}
}
]
}
最小,但足以說明要點。 現在,聚合語句:
db.chairs.aggregate([
// Normal query matching, which is good
{ "$match": { "type": "chair" } },
// Unwind the array to de-normalize
{ "$unwind": "$versions" },
// Group by the document in order to get the "first" array element
{ "$group": {
"_id": "$_id",
"chairtype": { "$first": "$chairtype" },
"versions": { "$first": "$versions" }
}},
// Then group by "chairtype" to get your average values
{ "$group": {
"_id": "$chairtype",
"MID": {"$avg": "$versions.content.value"}
}}
])
當然,如果您的實際文檔具有嵌套數組,那么您將“展開”並“匹配”所需的元素。 但這是將數組內容“縮小”到所需元素的一般過程。
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