equals
On this page
Definition
Syntax
equals has the following syntax:
{ $search: { "index": <index name>, // optional, defaults to "default" "equals": { "path": "<field-to-search>", "value": <boolean-value>|<objectId>, "score": <score-options> } } }
Options
equals uses the following terms to construct a query:
Field | Type | Description | Required? |
|---|---|---|---|
path | string | Indexed field to search. | yes |
value | Value to query for. | yes | |
score | object | Score assigned to matching search term results. Use one of the following options to modify the score:
For information on using | no |
Behavior
equals uses constant scoring. Each matching document receives
a score of 1 for each search clause matched. A document that matches
one search clause receives a score of 1, while a document that matches
three search clauses receives a score of 3. See the
Examples section for scoring examples.
Examples
The examples on this page use a collection named users containing the
following three documents:
{ "_id" : ObjectId("5ed698faa1199b471010d70c"), "name" : "Jim Hall", "verified_user" : true, "teammates" : [ ObjectId("5a9427648b0beebeb69579d0"), ObjectId("59b99dbdcfa9a34dcd7885c8") ], "region" : "East" } { "_id" : ObjectId("5ed6990aa1199b471010d70d"), "name" : "Ellen Smith", "verified_user" : true, "teammates" : [ ObjectId("5a9427648b0beebeb69537a5"), ObjectId("59b99dbdcfa9a34dcd7881d1") ], "region" : "Southwest" } { "_id" : ObjectId("5ed6994fa1199b471010d70e"), "name" : "Fred Osgood", "verified_user" : false, "teammates" : [ ObjectId("5a9427648b0beebeb69589a1"), ObjectId("59b99dbdcfa9a34dcd7897d3") ], "region" : "Northwest" }
The users collection is indexed with the following index definition:
{ "mappings": { "dynamic": false, "fields": { "teammates": { "type": "objectId" }, "verified_user": { "type": "boolean" }, "region": { "type": "string" } } } }
Basic Examples
The following example uses the equals operator to search the users
collection for documents in which the verified_user field is set to
true.
db.users.aggregate([ { "$search": { "equals": { "path": "verified_user", "value": true } } }, { "$project": { "name": 1, "_id": 0, "score": { "$meta": "searchScore" } } } ])
The above query returns the following results:
{ "name" : "Jim Hall", "score" : 1 } { "name" : "Ellen Smith", "score" : 1 }
The documents for "Jim Hall" and "Ellen Smith" each receive a score of 1
because those documents have the verified_user field set to true.
The following example uses the equals operator to search the users
collection for documents in which the teammates field contains the value
ObjectId("5a9427648b0beebeb69589a1").
db.users.aggregate([ { "$search": { "equals": { "path": "teammates", "value": ObjectId("5a9427648b0beebeb69589a1") } } } ])
The above query returns the document for "Fred Osgood", because that document
contains ObjectId("5a9427648b0beebeb69589a1") in the teammates array.
Compound Examples
The following example uses the compound operator in
conjunction with must, mustNot, and equals to search for documents
in which the region field is Southwest and the verified_user field
is not false.
db.users.aggregate([ { "$search": { "compound": { "must": { "text": { "path": "region", "query": "Southwest" } }, "mustNot": { "equals": { "path": "verified_user", "value": false } } } } } ])
The above query returns the document for "Ellen Smith", which is the only one in the collection which meets the search criteria.
The following example query has these search criteria:
- The
verified_userfield must be set totrue One of the following must be true:
- The
teammatesarray contains the valueObjectId("5a9427648b0beebeb69579d0") - The
regionfield is set toNorthwest
- The
db.users.aggregate([ { "$search": { "compound": { "must": { "equals": { "path": "verified_user", "value": true } }, "should": [ { "equals": { "path": "teammates", "value": ObjectId("5a9427648b0beebeb69579d0") } }, { "text": { "path": "region", "query": "Northwest" } } ], "minimumShouldMatch": 1 } } }, { "$project": { "name": 1, "_id": 0, "score": { "$meta": "searchScore" } } } ])
The above query returns the following results:
{ "name" : "Jim Hall", "score" : 2 }
The document for "Jim Hall" receives a score of 2 because it meets the
requirements for the must clause and the first of the two should clauses.
You can search for multiple ObjectIDs with a compound query. The following
example query uses the compound operator with a should clause
to search for three different ObjectIDs, at least two of which must appear
to satisfy the query.
db.users.aggregate([ { "$search": { "compound": { "should": [ { "equals": { "path": "teammates", "value": ObjectId("5a9427648b0beebeb69537a5") } }, { "equals": { "path": "teammates", "value": ObjectId("59b99dbdcfa9a34dcd7881d1") } }, { "equals": { "path": "teammates", "value": ObjectId("5a9427648b0beebeb69579d0") } } ], "minimumShouldMatch": 2 } } }, { "$project": { "name": 1, "_id": 0, "score": { "$meta": "searchScore" } } } ])
The above query returns the following results:
{ "name" : "Ellen Smith", "score" : 2 }
The document for "Ellen Smith" receives a score of 2 because it contains
two of the specified ObjectIDs in its teammates array.