How to search value in two Array in MongoDB

Question

I have some data in MongoDB, the data structure is like

{"a":{"b":[1,2,3,4,5],"c":[a,b,c,d,e]}}

1--->a
2--->b
3--->c
4--->d
5--->e

I want get the right part value by the left like search b by 2

How can I do this Thank you very much

what is the purpose of the b array? Am I getting it correct: you have some value X which has the index i inside b field. You want to get the ith element of c array? — bagrat
– bagrat, Commented May 18, 2015 at 14:09
I'm afraid this is not possible to achieve in an easy way, if it is possible at all. Are you bound to this structure or you can modify your model? — bagrat
– bagrat, Commented May 18, 2015 at 14:18
Well, thank you very much, The real data of b field is like 101.321, I set the b field as key and c field as value, but MongoDB seems like doesn't support key contains dot(.) — Jason Z
– Jason Z, Commented May 18, 2015 at 14:27

bagrat · Accepted Answer · 2015-05-18 14:52:48Z

1

What I would suggest is to modify your structure to be able to make a query you want. My suggested structure is the following:

{
   a: [
         {b: 1, c: "a"},
         {b: 2, c: "b"},
               .
               .
               .
      ]
}

Then having your b value, you will be able to get the c one:

db.yourCollection.find({"a.b": "your_b_value"})

UPDATE by request of the question author

To make your query by range execute the following query:

db.yourCollection.find({"a.b": {$gte: 400.0}, "a.b": {$lte: 400.3}})

answered May 18, 2015 at 14:25

bagrat

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