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equals

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  • Definition
  • Syntax
  • Options
  • Scoring Behavior
  • Examples
  • Sample Collection
  • Sample Index
  • Basic Example Queries
  • Compound Example Queries

Definition

equals

The equals operator checks whether a field matches a value you specify. equals supports querying the following data types:

You can use the equals operator to query booleans, objectIds, numbers, dates, and strings (indexed as token type) in arrays. If at least one element in the array matches the "value" field in the equals operator, Atlas Search adds the document to the result set.

Note

The equals operator supports numbers up to 15 decimal digits. Additional decimal digits in documents or queries can cause precision issues or query inaccuracy.

Syntax

equals has the following syntax:

{
   $search: {
      "index": <index name>, // optional, defaults to "default"
      "equals": {
         "path": "<field-to-search>",
         "value": <boolean-value>|<objectId>|<number>|<date>|<string>,
         "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
boolean, objectId, number, date, string, uuid, or null.
Value to query for.
yes
score
object

Score to assign to matching search term results. Use one of the following options to modify the score:

  • boost: multiply the result score by the given number.

  • constant: replace the result score with the given number.

  • function: replace the result score with the given expression.

For information on using score in your query, see Score the Documents in the Results.

no

Scoring Behavior

By default, equals uses constant scoring. Each matching document receives a score of 1.

When you query values in arrays, Atlas Search doesn't alter the score of the matching results based on the number of values inside the array that matched the query. The score would be the same as a single match regardless of the number of matches inside an array.

See the Examples section for scoring examples.

Examples

Sample Collection

The examples on this page use a collection named users containing the following three documents:

Note

The following example uses Javascript format. You can use the mongosh to add these documents in this format. The Atlas UI requires JSON format.

Sample Index

The users collection is indexed with the following index definition:

{
  "mappings": {
    "dynamic": true,
    "fields": {
      "name": {
        "type": "token",
        "normalizer": "lowercase"
      }
    }
  }
}

The index definition specifies the following:

  • Automatically index all dynamically indexable fields.

  • Index the name field as type token to support string search using the equals operator.

To learn how to create an Atlas Search index, see Create an Atlas Search Index.

Basic Example Queries

Boolean 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 account.new_user field contains the boolean value true.

db.users.aggregate([
  {
    "$search": {
      "equals": {
        "path": "account.new_user",
        "value": true
      }
    }
  }
])

The preceding query returns the document for "Jim Hall" because that document contains "new_user": true in the account object.

ObjectId Example

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 preceding query returns the document for "Fred Osgood" because that document contains ObjectId("5a9427648b0beebeb69589a1") in the teammates array.

Date Example

The following example uses the equals operator to search the users collection for documents in which the account_created field contains the value that matches ISODate("2022-05-04T05:01:08.000+00:00").

db.users.aggregate([
  {
    "$search": {
      "equals": {
        "path": "account_created",
        "value": ISODate("2022-05-04T05:01:08.000+00:00")
      }
    }
  }
])

The preceding query returns the document for "Ellen Smith" because that document contains "account_created": 2022-05-04T05:01:08.000+00:00.

Number Example

The following example uses the equals operator to search the users collection for documents in which the employee_number field contains the value that matches 259.

db.users.aggregate([
  {
    "$search": {
      "equals": {
        "path": "employee_number",
        "value": 259
      }
    }
  }
])

The preceding query returns the document for "Fred Osgood" because that document contains "employee_number": 259.

String Example

The following example uses the equals operator to search the users collection for documents in which the name field contains the value that matches Jim Hall.

db.users.aggregate([
  {
    "$search": {
      "equals": {
        "path": "name",
        "value": "jim hall"
      }
    }
  }
])

The preceding query returns the document for "Jim Hall" because that document contains Jim Hall in the name field. Atlas Search matches the lowercase query to the uppercase value in the document because it normalizes the term to lowercase as specified in the index definition for the name field.

UUID Example

The following example uses the equals operator to search the users collection for documents in which the uuid field contains the value that matches a specific UUID.

db.users.aggregate([
  {
    "$search": {
      "equals": {
        "path": "uuid",
        "value": UUID("fac32260-b511-4c69-8485-a2be5b7dda9e")
      }
    }
  }
])

Null Example

The following example uses the equals operator to search the users collection for documents in which the a field contains a null value.

db.users.aggregate([
  {
    $search: {
      "equals": {
        "path": "a",
          "query": null
        }
      }
    }
  ])

Compound Example Queries

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_user field must be set to true

  • One of the following must be true:

    • The teammates array contains the value ObjectId("5ed6990aa1199b471010d70d")

    • The region field is set to Northwest

db.users.aggregate([
  {
    "$search": {
      "compound": {
        "must": {
          "equals": {
            "path": "verified_user",
            "value": true
          }
        },
        "should": [
          {
            "equals": {
              "path": "teammates",
              "value": ObjectId("5ed6990aa1199b471010d70d")
            }
          },
          {
            "text": {
              "path": "region",
              "query": "Northwest"
            }
          }
        ],
        "minimumShouldMatch": 1
        }
      }
    },
    {
      "$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.

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