Mongodb count all value with different key

Question

Is there any way in monogdb to group all value with different key. Below is my data structure:

So my question is how can i count all 0/0 0/1 occurrence times? I have googled for a while and all answers i got with the same key. but you can see my keys inside samples are not the same. So any help will be appreciated.

s7vr · Accepted Answer · 2018-03-22 01:52:03Z

1

You can try below aggregation in 3.4.

Use $objectToArray to transform object to array of key value pairs followed by $unwind and $group on value to count occurrences.

db.col.aggregate([
  {"$addFields":{"samples":{"$objectToArray":"$samples"}}},
  {"$unwind":"$samples"},
  {"$group":{"_id":"$samples.v","count":{"$sum":1}}}
])

answered Mar 22, 2018 at 1:52

s7vr

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2 Comments

Crabime Over a year ago

thanks, but here i can not use objectToArray function, whether is there any other way to do that?

s7vr Over a year ago

Np. I'm afraid there is not a way on server side. You have to do it client side. Can you change structure to store the values as array ? like samples:[{k:b56, v:0/1}, ....]

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