DOCSP-10258 window functions

Author: jason-price-mongodb

source/reference/operator/aggregation.txt

@@ -1132,15 +1132,11 @@ Alphabetical Listing of Expression Operators
    /reference/operator/aggregation/convert
    /reference/operator/aggregation/cos
    /reference/operator/aggregation/cosh
-<<<<<<< HEAD
-   /reference/operator/aggregation/count-accum
-   /reference/operator/aggregation/dateAdd
-   /reference/operator/aggregation/dateDiff
-=======
    /reference/operator/aggregation/count-accumulator
    /reference/operator/aggregation/covariancePop
    /reference/operator/aggregation/covarianceSamp
->>>>>>> f7253052c... DOCSP-10258 window functions
+   /reference/operator/aggregation/dateAdd
+   /reference/operator/aggregation/dateDiff
    /reference/operator/aggregation/dateFromParts
    /reference/operator/aggregation/dateSubtract
    /reference/operator/aggregation/dateToParts

source/reference/operator/aggregation/count-accum.txt

@@ -19,8 +19,7 @@ Definition
 
 Returns the number of documents.
 
-.. admonition:: Disambiguation
-   :class: note
+.. note:: Disambiguation
 
    This page describes the ``$count`` aggregation accumulator. For the
    ``$count`` aggregation pipeline stage, see :pipeline:`$count
@@ -47,6 +46,16 @@ Returns the number of documents.
 
 :group:`$count` does not accept any parameters.
 
+Behavior
+--------
+
+:group:`$count` is functionally equivalent to using ``{ $sum : 1 }``
+within the :pipeline:`$group` stage.
+
+.. seealso::
+
+   :group:`$sum`
+
 Examples
 --------
 

source/reference/operator/aggregation/count-accumulator.txt

@@ -20,8 +20,7 @@ Definition
    Passes a document to the next stage that contains a count of the
    number of documents input to the stage.
 
-   .. admonition:: Disambiguation
-      :class: note
+   .. note:: Disambiguation
 
       This page describes the ``$count`` aggregation pipeline stage.
       For the ``$count`` aggregation accumulator, see :group:`$count

source/reference/operator/aggregation/count.txt

@@ -23,8 +23,7 @@ documents. Only meaningful when documents are in a defined order.
 
 .. include:: /includes/extracts/fact-aggregation-accumulator-first.rst
 
-.. admonition:: Disambiguation
-   :class: note
+.. note:: Disambiguation
 
    This page describes the :group:`$first` aggregation accumulator. For
    the :expression:`$first` array operator, see :expression:`$first

source/reference/operator/aggregation/first.txt

@@ -59,9 +59,9 @@ documents forming a trapezoid using the:
        Specifies the :ref:`expression <aggregation-expressions>` to
        evaluate. You must provide an expression that returns a number.
 
-   * - :ref:`unit <integral-outputUnit>`
+   * - :ref:`unit <integral-unit>`
 
-     - .. _integral-outputUnit:
+     - .. _integral-unit:
 
        .. include:: /includes/outputUnit-behavior.rst
 

source/reference/operator/aggregation/integral.txt

@@ -23,8 +23,7 @@ Only meaningful when documents are in a defined order.
 
 .. include:: /includes/extracts/fact-aggregation-accumulator-last.rst
 
-.. admonition:: Disambiguation
-   :class: note
+.. note:: Disambiguation
 
    This page describes the :group:`$last` aggregation accumulator. For
    the :expression:`$last` array operator, see :expression:`$last (array

source/reference/operator/aggregation/last.txt

@@ -40,8 +40,9 @@ MongoDB 5.0 introduces the following aggregation operators:
 
    * - :group:`$count`
      - :group:`$count (aggregation accumulator) <$count>` 
-       provides a count of all documents when used in a 
-       :pipeline:`$group (aggregation) <$group>` pipeline stage.
+       provides a count of all documents when used in the existing
+       pipeline :pipeline:`$group (aggregation) <$group>` stage and the
+       new MongoDB 5.0 :pipeline:`$setWindowFields` stage.
 
        .. note:: Disambiguation