我在 mongodb 中有这些数据。
有人能帮助求出这里的总平均数吗?谢谢!!
{
"name": "FooBar",
"__v": 0,
"user_rating": [
{
"date": "2017-06-02T16:19:32.002Z",
"user_rating": 5,
},
{
"date": "2017-06-02T16:19:46.803Z",
"user_rating": 3,
},
{
"date": "2017-06-02T16:20:01.244Z",
"user_rating": 5,
},
{
"date": "2017-06-02T16:15:54.673Z",
"user_rating": 3,
},
{
"date": "2017-06-02T16:53:42.489Z",
"user_rating": 5,
}
]
}
我需要筛选并显示店铺名称、平均评分、总评分数量以及5星评分数量、4星评分数量等信息。
这是我的期望结果:
[
{
"_id":"FooBar",
"countRating":5,
"averageRating":4.2,
"ratings": [
{"num":3,"count":2},
{"num":5,"count":3}
]
}
]
然而,我似乎无法获取averageRating - 相反,我得到了每个评级的两个组合总数的平均值。
这是我的Mongo查询:
db.collection.aggregate([
{
$match: {"name": "FooBar"}
},
{
$unwind: "$user_rating"
},
{
$match: {"name": "FooBar"}
},
{
$group: {
_id: {
"name": "$name",
"rating": "$user_rating.user_rating"
},
averageRating: {$avg: "$user_rating.user_rating"},
countRating: {$sum: 1}
}
},
{
$group: {
_id: "$_id.name",
countRating: {"$sum": "$totalRatings"},
averageRating: {"$avg": "$averageRating"},
"rating": {
"$push": {
"num": "$_id.rating",
"count": "$totalRatings"
}
},
}
}]);
有人能帮助求出这里的总平均数吗?谢谢!!