Question 115271 in Mongodb Question posted in
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how to find documents from mongoDB using pymongo by statement – < if there is a key containing certain string "X" >

{    
    "_id" : ObjectId("639789e84500571417ii9343"),
    "72uebaa27279b22p348e61870a6a8840something" : [ 
        {
            "price" : 130,
            "date" : 1670874476
        }, 
        {
            "price" : 107,
            "date" : 1672258500
        }
    ]
}

I need to find all documents where the second key contains string "something".

I only found a way to find by key name with "$exists", but I couldn’t find documents by statement mentioned above.

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2

Answers


  1. 0

    You can use the following methods to perform a query in MongoDB with “like” regex:

    • Method 1: Find Documents that Contain String
    db.collection.find({name: {$regex : /string/i}})

    Note that the i indicates a case-insensitive match.

    • Method 2: Find Documents that Start with String
    db.collection.find({name: {$regex : /^string/i}})
    • Method 3: Find Documents that End with String
    db.collection.find({name: {$regex : /string$/i}})
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  2. 0

    There is no way to query a fieldname with a substring or regular expression.

    It is possible to do that with aggregation, but this is not something an index can help with, so it will probably not perform well, and won’t scale well, because every such query would have to examine and process every document in the collection.

    The pipeline would need to:

    • convert the object to an array so the fieldname can be considered as data
    • match the desired critera
    • remove temporary fields or reconstitute the object
    db.collection.aggregate([
  {$addFields:{ arraydoc: {$objectToArray: "$$ROOT"}}},
  {$match: { "arraydoc.k": {$regex: "something"}}},
  {$project:{ arraydoc: 0}}
])

    Playground

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