将文本字段上的匹配与聚合相结合 [英] Combining match on text field with aggregate

问题描述

运行以下语句:

db.users.aggregate(
   [
       { $match : { "confirmed" : {$eq: "true" } } },
       { $group : { _id : "$email", email: { $push: "$email" } } }
   ]
)

给我零结果，虽然以下一个工作得非常好，给出~12k:

Gives me zero results, although the following one works perfectly fine giving ~12k:

db.getCollection('users').find({confirmed:"true"})

问题:如何正确组合匹配和分组?我基本上是在寻找 SELECT email FROM users GROUP BY email

Question: how do I combined match and group properly? I am basically looking for a SELECT email FROM users GROUP BY email

附加: SELECT email, count(*) FROM users GROUP BY email 将是我的长期目标，但我似乎无法理解mongodb :(

Add on: SELECT email, count(*) FROM users GROUP BY email would be my long term goal, but I can't seem to get my head around mongodb :(

推荐答案

db.users.aggregate(
   [
       { $match : { "confirmed" : "true" }  },
       { $group : { _id : "$email",count:{$sum:1} } }
   ]
)

`请检查 true 是否为布尔值，如果布尔值不需要将其检查为字符串，它将为您提供 0 文档.只是确认:真实

` please check if true is boolean if boolean than no need to check it as a string it will give you 0 document.just Confirmed:true

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