Table of Contents
MongoDB queries can be used to compare values using the greater than (>) and less than (<) operators. These operators are useful for finding documents that have values greater than or less than a certain value. For example, you can use these operators to find documents with values that are greater than 20 or less than 10. You can also use these operators to compare strings, dates, and arrays.
You can use the following operators in MongoDB to perform greater than or less than queries:
- $lt: Less than
- $lte: Less than or equal
- $gt: Greater than
- $gte: Greater than or equal
The following methods show common ways to use these operators:
Method 1: Greater Than Query
db.myCollection.find({field1: {$gt:25}})
Method 2: Less Than Query
db.myCollection.find({field1: {$lt:25}})
Method 3: Greater Than and Less Than Query
db.myCollection.find({field1: {$gt:25, $lt:32}})
Method 4: Greater Than or Less Than Query
db.myCollection.find({ "$or": [ {"field1": {$gt: 30}}, {"field1": {$lt: 20}} ] })
The following examples show how to use each method in practice with a collection teams with the following documents:
db.teams.insertOne({team: "Mavs", points: 31})
db.teams.insertOne({team: "Spurs", points: 22})
db.teams.insertOne({team: "Rockets", points: 19})
db.teams.insertOne({team: "Warriors", points: 26})
db.teams.insertOne({team: "Cavs", points: 33})
Example 1: Greater Than Query
The following code shows how to query for all documents where the value in the “points” field is greater than 25:
db.teams.find({points: {$gt:25}})
This query returns the following documents:
{ _id: ObjectId("6203e4a91e95a9885e1e764f"),
team: 'Mavs',
points: 31 }
{ _id: ObjectId("6203e4a91e95a9885e1e7652"),
team: 'Warriors',
points: 26 }
{ _id: ObjectId("6203e4a91e95a9885e1e7653"),
team: 'Cavs',
points: 33 }
Notice that each of the three documents in the output have a value in the “points” field greater than 25.
Example 2: Less Than Query
The following code shows how to query for all documents where the value in the “points” field is less than 25:
db.teams.find({points: {$lt:25}})
This query returns the following documents:
{ _id: ObjectId("6203e4a91e95a9885e1e7650"),
team: 'Spurs',
points: 22 }
{ _id: ObjectId("6203e4a91e95a9885e1e7651"),
team: 'Rockets',
points: 19 }
Notice that both of the documents in the output have a value in the “points” field less than 25.
Example 3: Greater Than and Less Than
The following code shows how to query for all documents where the value in the “points” field is greater than 25 and less than 32:
db.teams.find({points: {$gt:25, $lt:32}})
This query returns the following documents:
{ _id: ObjectId("6203e4a91e95a9885e1e764f"),
team: 'Mavs',
points: 31 }
{ _id: ObjectId("6203e4a91e95a9885e1e7652"),
team: 'Warriors',
points: 26 }
Notice that both of the documents in the output have a value in the “points” field greater than 25 and less than 32.
Example 4: Greater Than or Less Than
The following code shows how to query for all documents where the value in the “points” field is greater than 30 or less than 20:
db.teams.find({ "$or": [ {"points": {$gt: 30}}, {"points": {$lt: 20}} ] })
This query returns the following documents:
{ _id: ObjectId("6203e4a91e95a9885e1e764f"),
team: 'Mavs',
points: 31 }
{ _id: ObjectId("6203e4a91e95a9885e1e7651"),
team: 'Rockets',
points: 19 }
{ _id: ObjectId("6203e4a91e95a9885e1e7653"),
team: 'Cavs',
points: 33 }
Notice that each of the documents in the output have a value in the “points” field greater than 30 or less than 20.
The following tutorials explain how to perform other common operations in MongoDB: