Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-14872

Aggregation pipeline project expression operator to concatenate multiple arrays into one

    XMLWordPrintable

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.1.5
    • Component/s: Aggregation Framework
    • Labels:
      None
    • Backwards Compatibility:
      Fully Compatible
    • Sprint:
      Quint Iteration 4, Quint Iteration 5

      Description

      I need to count the number of duplicate IDs that occur across all documents in a collection. However, this very simple aggregation is complicated by the fact that the IDs in question may appear in multiple fields in the input document.

      Suppose I have input documents like the one below:

      {
      		 
        a : [1, 2, 3],
      		 
        b : [2, 4, 5]
      		 
      }

      I'd like to transform this to a document that looks like:

      {
      		 
        c : [1, 2, 3, 2, 4, 5]
      		 
      }

      From this point, it is straightforward to unwind and group on c to get to the desired result.

      The above transformation is similar to what would be achieved using the $setUnion operator, but here I do not want to filter out duplicate values.

      Therefore, this request is for an operator similar to $setUnion but which does not filter out duplicate values.

        Attachments

          Issue Links

          is duplicated by

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-5919 Add set/array operations to $unwind in new aggregation framework

          • Minor - P4 - Minor loss of function, or other problem where easy workaround is present.
          • Closed
          is related to

          New Feature - A new feature of the product, which has yet to be developed. SERVER-17258 Add $reduce expression operator for rollup of arrays

          • Major - P3 - Major loss of function.
          • Closed
          related to

          New Feature - A new feature of the product, which has yet to be developed. CSHARP-1364 Aggregation pipeline project expression operator to concatenate multiple arrays into one

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. DRIVERS-234 Aggregation Builder Support for 3.2

          • Major - P3 - Major loss of function.
          • Closed

            Activity

              People

              • Votes:
                1 Vote for this issue
                Watchers:
                9 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: