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我想寫一個蒙戈DB查詢,我做到以下幾點,蒙戈DB - 集團BY和HAVING實施
JSON列表 - 代表我的收藏文件,
行業】:
{
"_id" : ObjectId("57aa6058be0c853c8cee34cd"),
"options": {
"paramList" : [
{
"name" : "industryCategory",
"value" : "Travel",
"mandatory" : true
},
{
"name" : "someOtherThing",
"value" : "dontMind",
"mandatory" : true
}
]
}
"mostRecent" : true
},
{
"_id" : ObjectId("57aa6058be0c853c8cee34cd"),
"options": {
"paramList" : [
{
"name" : "industryCategory",
"value" : "Dining",
"mandatory" : true
},
{
"name" : "someOtherThing",
"value" : "dontMind",
"mandatory" : true
}
]
}
"mostRecent" : true
},
{
"_id" : ObjectId("57aa6058be0c853c8cee34cd"),
"options": {
"paramList" : [
{
"name" : "industryCategory",
"value" : "Travel",
"mandatory" : true
},
{
"name" : "someOtherThing",
"value" : "dontMind",
"mandatory" : true
}
]
}
"mostRecent" : true
}
我想分組並獲得這些paramList值的計數,其中name是industryCategory。從本質上講,我期待的輸出是這樣的,
Travel: 2
Dining: 1
我試圖做到以下幾點,
產業是集名稱,
db.Industry.aggregate (
[
{$match: {mostRecent: true}},
{$group: {
_id: '$options.paramList.value',
count: {$sum: 1}
}},
{$match: {'options.paramList.name': 'industryCategory'}}
])
我得到一個空的結果。請建議我能做些什麼