Javascript mongodb聚合筛选器和节点上的计数
我把这个集合命名为“点” 我还有另一个名字叫“小溪” 我需要在我想要搜索包含字母“o”的Javascript mongodb聚合筛选器和节点上的计数,javascript,node.js,mongodb,aggregation-framework,mongodb-aggregation,Javascript,Node.js,Mongodb,Aggregation Framework,Mongodb Aggregation,我把这个集合命名为“点” 我还有另一个名字叫“小溪” 我需要在我想要搜索包含字母“o”的电子邮件的地方进行聚合查询。我期望的结果是这样的 [ { 'guid': 'aaa', items: 2 }, { 'guid': 'bbb', item: 1 }, { 'guid': 'ccc', item: 0 }, ] 我已经这样做了 db.getCollection('points').aggregate([ { $lookup: {
电子邮件的地方进行聚合查询。我期望的结果是这样的
[
{ 'guid': 'aaa', items: 2 },
{ 'guid': 'bbb', item: 1 },
{ 'guid': 'ccc', item: 0 },
]
我已经这样做了
db.getCollection('points').aggregate([
{
$lookup: {
from: "stream",
localField: "guid",
foreignField: "guid",
as: "items"
}
},
{
$project: {
_id: 0,
guid: 1,
items: {
$size: "$items"
}
}
}
]);
如果我在mysql中,查询将如下
SELECT DISTINCT
points.guid,
(
SELECT COUNT(*)
FROM stream
WHERE guid = stream.guid and stream.email like '%o%'
) AS items
FROM points
答案是根据评论编辑的
您可以尝试以下聚合管道
db.getCollection("points").aggregate([
{"$lookup":{"from":"stream", "localField":"guid", "foreignField":"guid", as:"items"}},
{"$unwind":"$items"},
{"$group":{"_id": "$guid", "guid":{"$first":"$guid"}, "emails":{"$push":"$items.email"}}},
{"$project":{"guid" :1, "emails":{"$setUnion":["$emails", [{"$literal":"io"}]]}}},
{"$unwind":"$emails"},
{"$match":{"emails":/[io]/}},
{"$group":{"_id":"$guid", "items":{"$sum":1}}},
{"$project":{"_id":0, "guid":"$_id", "items":{"$add":["$items", -1]}}}
])
样本输出:
{ "items" : 3, "guid" : "aaa" }
{ "items" : 1, "guid" : "ccc" }
{ "items" : 1, "guid" : "bbb" }
注意:我引入了一个满足匹配条件的虚拟电子邮件id—“oi”,以确保点采集的数据不会丢失。为了补偿这个伪字段,最后从计数中减去-1。做得好,但如果需要,请从流中选择count(*),其中guid=stream.guid和(stream.email,如“%o%”或stream.email,如“%I%”)thanks@MauroSala:更新了我的答案。但是您的所有电子邮件在“disney”中都有“i”…我需要用很多这样的内容进行查询:从流中选择COUNT(*),其中guid=stream.guid和(stream.email如“%o%”或stream.title如“%i%”,但您的答案是正确的
db.getCollection("points").aggregate([
{"$lookup":{"from":"stream", "localField":"guid", "foreignField":"guid", as:"items"}},
{"$unwind":"$items"},
{"$group":{"_id": "$guid", "guid":{"$first":"$guid"}, "emails":{"$push":"$items.email"}}},
{"$project":{"guid" :1, "emails":{"$setUnion":["$emails", [{"$literal":"io"}]]}}},
{"$unwind":"$emails"},
{"$match":{"emails":/[io]/}},
{"$group":{"_id":"$guid", "items":{"$sum":1}}},
{"$project":{"_id":0, "guid":"$_id", "items":{"$add":["$items", -1]}}}
])
{ "items" : 3, "guid" : "aaa" }
{ "items" : 1, "guid" : "ccc" }
{ "items" : 1, "guid" : "bbb" }