Details
-
New Feature
-
Resolution: Duplicate
-
Major - P3
-
None
-
None
-
None
-
(copied to CRM)
Description
Example function:
db.coll.insert({id: 'foo', a: 100, b: 200, c: 300, d: {e: 400, f:500}})
|
db.coll.aggregate([
|
{$docUnwind: {id: 0}}, // syntax similar to $project for whitelisting or blacklisting which fields to unwind
|
])
|
{id: 'foo', f_name: 'a', f_value: 100}
|
{id: 'foo', f_name: 'b', f_value: 200}
|
{id: 'foo', f_name: 'c', f_value: 300}
|
{id: 'foo', f_name: 'd.e', f_value: 400}
|
{id: 'foo', f_name: 'd.f', f_value: 500}
|
In short, it will take the fields in a document, and unwind a portion of them into name, value pairs, making a separate document for each.
One use case for this is collecting statistics across a dynamic list of fields.
Attachments
Issue Links
- duplicates
-
SERVER-11392 $unwind on subdocuments
-
- Closed
-