and.txt

==================
$and (aggregation)
==================

.. default-domain:: mongodb

.. contents:: On this page
   :local:
   :backlinks: none
   :depth: 1
   :class: singlecol

Definition
----------

.. expression:: $and

   Evaluates one or more expressions and returns ``true`` if *all* of
   the expressions are ``true`` or if run with no argument
   expressions. Otherwise, :expression:`$and` returns ``false``.

   :expression:`$and` syntax:

   .. code-block:: javascript

      { $and: [ <expression1>, <expression2>, ... ] }

   For more information on expressions, see
   :ref:`aggregation-expressions`.

.. _and-boolean-behavior:

Behavior
--------

.. include:: /includes/extracts/fact-agg-boolean-and.rst

.. list-table::
   :header-rows: 1
   :widths: 70 15

   * - Example

     - Result

   * - ``{ $and: [ 1, "green" ] }``

     - ``true``

   * - ``{ $and: [ ] }``

     - ``true``

   * - ``{ $and: [ [ null ], [ false ], [ 0 ] ] }``

     - ``true``

   * - ``{ $and: [ null, true ] }``

     - ``false``

   * - ``{ $and: [ 0, true ] }``

     - ``false``

Error Handling
--------------

.. |and-or| replace:: ``$and``
.. |true-false| replace:: ``false``

.. include:: /includes/and-or-behavior.rst

.. code-block:: javascript

   db.example.find( {
      $and: [
         { x: { $ne: 0 } },
         { $expr: { $eq: [ { $divide: [ 1, "$x" ] }, 3 ] } }
      ]
   } )

Example
-------

Create an example ``inventory`` collection with these documents:

.. code-block:: javascript

   db.inventory.insertMany([
      { "_id" : 1, "item" : "abc1", description: "product 1", qty: 300 },
      { "_id" : 2, "item" : "abc2", description: "product 2", qty: 200 },
      { "_id" : 3, "item" : "xyz1", description: "product 3", qty: 250 },
      { "_id" : 4, "item" : "VWZ1", description: "product 4", qty: 300 },
      { "_id" : 5, "item" : "VWZ2", description: "product 5", qty: 180 }
   ])

This operation uses the :expression:`$and` operator to
determine if ``qty`` is greater than 100 *and* less than ``250``:

.. code-block:: javascript

   db.inventory.aggregate(
      [
        {
          $project:
             {
               item: 1,
               qty: 1,
               result: { $and: [ { $gt: [ "$qty", 100 ] }, { $lt: [ "$qty", 250 ] } ] }
             }
        }
      ]
   )

The operation returns these results:

.. code-block:: javascript

   { "_id" : 1, "item" : "abc1", "qty" : 300, "result" : false }
   { "_id" : 2, "item" : "abc2", "qty" : 200, "result" : true }
   { "_id" : 3, "item" : "xyz1", "qty" : 250, "result" : false }
   { "_id" : 4, "item" : "VWZ1", "qty" : 300, "result" : false }
   { "_id" : 5, "item" : "VWZ2", "qty" : 180, "result" : true }