Question 116518 in Mongodb Question posted in
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how do i find last element of array list from MongoDB using aggregation function in spring?

db.getCollection(‘notification’).find({},{statusList:{$slice:-1}})
this query is getting expected outputs but from java, I could not find the solution for this. can anyone have a solution for this? I want to use only the aggregation function

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3

Answers


  1. 0

    the aggregation operator $last can be used to access the last element of an array:

    db.collection.aggregate([
  { $addFields: { last: { $last: "$yourArray" } } },
  { $match: { last: "C" } }
])

    or

     db.getCollection('notification').aggregate([
   {
     $project:
      {
         last: { statusList: [ "$slice", -1 ] }
      }
   }
])

    and you can also take reference from:
    MongoDB – Query on the last element of an array?

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  2. 0

    Try to use $last aggregation operator.

     db.getCollection('notification').aggregate([
   {
     $project:
      {
         _id: 0,
         last: { $last:"$statusList"}
      }
   }
])
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  3. 0

    Try with this, It gives the same output as $last:

     db.getCollection('notification').aggregate([
   {
     $project:
      {
         last: { $arrayElemAt: [ "$project", -1 ] }
      }
   }
])
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