exists¶

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Definition

Syntax
Examples

Definition¶

exists¶: The exists operator tests if a path to a specified indexed field name exists in a document. If the specified field exists but is not indexed, the document is not included with the result set. exists is often used as part of a compound query in conjunction with other search clauses.

Syntax¶

exists has the following syntax:

1 {
2   $search: {
3     "index": <index name>, // optional, defaults to "default"
4     "exists": {
5       "path": "<field-to-test-for>",
6     }
7   }
8 }

Examples¶

The examples on this page use a collection called fruit that contains the following documents:

1 {
2   "_id" : 1,
3   "type" : "apple",
4   "description" : "Apples come in several varieties, including Fuji, Granny Smith, and Honeycrisp."
5 },
6 {
7   "_id" : 2,
8   "type" : "banana",
9   "description" : "Bananas are usually sold in bunches of five or six."
10 },
11 { "_id" : 3,
12   "type": "apple",
13   "description" : "Apple pie and apple cobbler are popular apple-based desserts."
14 },
15 { "_id" : 4,
16   "description" : "Types of citrus fruit include lemons, oranges, and grapefruit.",
17   "quantities" : {
18     "lemons": 200,
19     "oranges": 240,
20     "grapefruit": 160
21   }
22 }

The fruit collection has an Atlas Search index on the description field that uses the standard analyzer. The standard analyzer lower-cases all words and disregards common stop words ("the", "a", "and", etc).

Basic Example¶

The following example searches for documents which include a field called type:

1 db.fruit.aggregate([
2   {
3     $search: {
4       "exists": {
5         "path": "type"
6       }
7     }
8   }
9 ])

The above query returns the first three documents of the collection. The document with _id: 4 is not included because it does not have a type field.

Embedded Example¶

Use dot notation to search for embedded fields. The following example searches for documents which have a field named lemons embedded within a field named quantities.

1 db.fruit.aggregate([
2   {
3     $search: {
4       "exists": {
5         "path": "quantities.lemons"
6       }
7     }
8   }
9 ])

The above query returns the following result:

1 {
2   "_id" : 4,
3   "description" : "Types of citrus fruit include lemons, oranges, and grapefruit.",
4   "quantities" : {
5     "lemons": 200,
6     "oranges": 240,
7     "grapefruit": 160
8   }
9 }

Compound Example¶

The following example uses exists as part of a compound query.

1 db.fruit.aggregate([
2   {
3     $search: {
4       "compound": {
5         "must": [
6           {
7             "exists": {
8               "path": "type"
9             }
10           },
11           {
12             "text": {
13               "query": "apple",
14               "path": "type"
15             }
16           }],
17         "should": {
18           "text": {
19             "query": "fuji",
20             "path": "description"
21           }
22         }
23       }
24     }
25   }
26 ])

The above query returns the following results:

1 {
2   "_id" : 1,
3   "type" : "apple",
4   "description" : "Apples come in several varieties, including Fuji, Granny Smith, and Honeycrisp."
5 }
6 {
7   "_id" : 3,
8   "type" : "apple",
9   "description" : "Apple pie and apple cobbler are popular apple-based desserts."
10 }

Both documents have a type field, and both include the search term apple. The document with _id: 1 is returned first because it satisfies the should clause.

← equals geoShape →

1	{
2	$search: {
3	"index": <index name>, // optional, defaults to "default"
4	"exists": {
5	"path": "<field-to-test-for>",
6	}
7	}
8	}

1	{
2	"_id" : 1,
3	"type" : "apple",
4	"description" : "Apples come in several varieties, including Fuji, Granny Smith, and Honeycrisp."
5	},
6	{
7	"_id" : 2,
8	"type" : "banana",
9	"description" : "Bananas are usually sold in bunches of five or six."
10	},
11	{ "_id" : 3,
12	"type": "apple",
13	"description" : "Apple pie and apple cobbler are popular apple-based desserts."
14	},
15	{ "_id" : 4,
16	"description" : "Types of citrus fruit include lemons, oranges, and grapefruit.",
17	"quantities" : {
18	"lemons": 200,
19	"oranges": 240,
20	"grapefruit": 160
21	}
22	}

1	db.fruit.aggregate([
2	{
3	$search: {
4	"exists": {
5	"path": "type"
6	}
7	}
8	}
9	])

1	{
2	"_id" : 4,
3	"description" : "Types of citrus fruit include lemons, oranges, and grapefruit.",
4	"quantities" : {
5	"lemons": 200,
6	"oranges": 240,
7	"grapefruit": 160
8	}
9	}

1	db.fruit.aggregate([
2	{
3	$search: {
4	"compound": {
5	"must": [
6	{
7	"exists": {
8	"path": "type"
9	}
10	},
11	{
12	"text": {
13	"query": "apple",
14	"path": "type"
15	}
16	}],
17	"should": {
18	"text": {
19	"query": "fuji",
20	"path": "description"
21	}
22	}
23	}
24	}
25	}
26	])