Docsp-19837 document first n last n (#148)

* DOCSP-19837 init

* DOCSP-19837

* DOCSP-19837

* *

* remove highest

* remove highest verbiage

* adjust to feedback

* *

* Add more context

* gameid to own line

* fix 275 code block indent

* *

* Address Mihai comments #1

* ***

* Added Aggregation Expression example and addressed Mickey Comments #1

* minor verbaige cleanup

* a aggregation expression -> an aggregation expression

* Updated based on latest TR feedback

* corrected input statement

* group key example for href

* Adjust lastFive... bullet point and output on both pages

* make aggregation.txt Available in... consistant with extracts-agg

* Address Katyas comments #1

* correct emphasize lines for last ex

* rebase

* fix spacing in 5.2

* Add distinct notes to all accumulators

* fix 5.2 build errors

* *

Author: ianf-mongodb

source/includes/extracts-agg-operators.yaml

@@ -1074,6 +1074,18 @@ content: |
 
              Available in :pipeline:`$setWindowFields` stage.
 
+      * - :group:`$firstN`
+
+        - Returns an aggregation of the first ``n`` elements within a group. 
+          Only meaningful when documents are in a defined order.
+          Distinct from the :expression:`$firstN` array operator.
+
+          .. versionadded:: 5.2
+
+             Available in :pipeline:`$group`, 
+             :ref:`expression <aggregation-expressions>` and 
+             :pipeline:`$setWindowFields` stages.
+
       * - :group:`$last`
 
         - Returns a value from the last document for each group. Order
@@ -1085,6 +1097,18 @@ content: |
 
              Available in :pipeline:`$setWindowFields` stage.
 
+      * - :group:`$lastN`
+
+        - Returns an aggregation of the last ``n`` elements within a group. 
+          Only meaningful when documents are in a defined order.
+          Distinct from the :expression:`$lastN` array operator.
+
+          .. versionadded:: 5.2
+
+             Available in :pipeline:`$group`, 
+             :ref:`expression <aggregation-expressions>` and 
+             :pipeline:`$setWindowFields` stages.
+
       * - :group:`$max`
 
         - Returns the highest expression value for each group.
@@ -1097,6 +1121,7 @@ content: |
 
         - Returns an aggregation of the ``n`` maximum valued elements in
           a group.
+          Distinct from the :expression:`$maxN` array operator.
 
           .. versionadded:: 5.2
 
@@ -1385,6 +1410,7 @@ content: |
 
         - Returns an aggregation of the ``n`` minimum valued elements in a
           group.
+          Distinct from the :expression:`$minN` array operator.
 
           .. versionadded:: 5.2
 

source/includes/setWindowFields-operators.rst

@@ -3,11 +3,12 @@ These operators can be used with the :pipeline:`$setWindowFields` stage:
 .. _setWindowFields-accumulator-operators:
 
 - Accumulator operators: :group:`$addToSet`, :group:`$avg`, 
-  :group:`$bottomN`, :group:`$count`, :group:`$covariancePop`, 
-  :group:`$covarianceSamp`, :group:`$derivative`, 
-  :group:`$expMovingAvg`, :group:`$integral`, :group:`$max`, :group:`$maxN`, 
-  :group:`$min`, :group:`$minN`, :group:`$push`, :group:`$stdDevSamp`,
-  :group:`$stdDevPop`, :group:`$sum` and :group:`$topN`.
+  :group:`$bottom`, :group:`$bottomN`, :group:`$count`, 
+  :group:`$covariancePop`, :group:`$covarianceSamp`, 
+  :group:`$derivative`, :group:`$expMovingAvg`, :group:`$firstN`, 
+  :group:`$integral`, :group:`$lastN`, :group:`$max`, :group:`$maxN`,
+  :group:`$min`, :group:`$minN`, :group:`$push`, :group:`$stdDevSamp`, 
+  :group:`$stdDevPop`, :group:`$sum`, :group:`$top`, :group:`$topN`.
 
 .. _setWindowFields-gap-filling-operators:
 

source/reference/operator/aggregation.txt

@@ -520,6 +520,18 @@ Alphabetical Listing of Expression Operators
 
        .. versionadded:: 5.2
 
+   * - :group:`$firstN`
+
+     - Returns an aggregation of the first ``n`` fields within a group.
+       Only meaningful when documents are in a defined order.
+       Distinct from the :expression:`$firstN` array operator.
+
+       .. versionadded:: 5.2
+
+       Available in :pipeline:`$group`, 
+       :ref:`expression <aggregation-expressions>` and 
+       :pipeline:`$setWindowFields` stages.
+
    * - :expression:`$floor`
 
      - Returns the largest integer less than or equal to the specified number.
@@ -659,6 +671,18 @@ Alphabetical Listing of Expression Operators
 
        .. versionadded:: 5.2 
 
+   * - :group:`$lastN`
+
+     - Returns an aggregation of the last ``n`` fields within a group.
+       Only meaningful when documents are in a defined order.
+       Distinct from the :expression:`$lastN` array operator.
+
+       .. versionadded:: 5.2
+
+       Available in :pipeline:`$group`, 
+       :ref:`expression <aggregation-expressions>` and 
+       :pipeline:`$setWindowFields` stages.
+
    * - :expression:`$let`
 
      - Defines variables for use within the scope of a subexpression and
@@ -735,6 +759,7 @@ Alphabetical Listing of Expression Operators
 
      - Returns an aggregation of the ``n`` maximum valued elements in a
        group.
+       Distinct from the :expression:`$maxN` array operator.
 
        .. versionadded:: 5.2
 
@@ -761,10 +786,18 @@ Alphabetical Listing of Expression Operators
 
           Available in :pipeline:`$setWindowFields` stage.
 
+   * - :expression:`$minN`
+
+     - Returns the ``n`` smallest values in an array.
+       Distinct from the :group:`$minN` accumulator.
+
+       .. versionadded:: 5.2
+
    * - :group:`$minN`
 
      - Returns an aggregation of the ``n`` minimum valued elements in a
        group.
+       Distinct from the :expression:`$minN` array operator.
 
        .. versionadded:: 5.2
 
@@ -1261,6 +1294,7 @@ Alphabetical Listing of Expression Operators
    /reference/operator/aggregation/avg
    /reference/operator/aggregation/binarySize
    /reference/operator/aggregation/bottom
+   /reference/operator/aggregation/bottomN
    /reference/operator/aggregation/bsonSize
    /reference/operator/aggregation/ceil
    /reference/operator/aggregation/cmp
@@ -1294,6 +1328,7 @@ Alphabetical Listing of Expression Operators
    /reference/operator/aggregation/expMovingAvg
    /reference/operator/aggregation/filter
    /reference/operator/aggregation/first
+   /reference/operator/aggregation/firstN
    /reference/operator/aggregation/first-array-element
    /reference/operator/aggregation/firstN-array-element
    /reference/operator/aggregation/floor
@@ -1314,6 +1349,7 @@ Alphabetical Listing of Expression Operators
    /reference/operator/aggregation/isoWeek
    /reference/operator/aggregation/isoWeekYear
    /reference/operator/aggregation/last
+   /reference/operator/aggregation/lastN
    /reference/operator/aggregation/last-array-element
    /reference/operator/aggregation/lastN-array-element
    /reference/operator/aggregation/let
@@ -1395,6 +1431,7 @@ Alphabetical Listing of Expression Operators
    /reference/operator/aggregation/toLong
    /reference/operator/aggregation/toObjectId
    /reference/operator/aggregation/top
+   /reference/operator/aggregation/topN
    /reference/operator/aggregation/toString
    /reference/operator/aggregation/toLower
    /reference/operator/aggregation/toUpper