Definition
- $gt
- $gtselects those documents where the value of the specified field is greater than (i.e.- >) the specified value.- For most data types, comparison operators only perform comparisons on fields where the BSON type matches the query value's type. MongoDB supports limited cross-BSON comparison through Type Bracketing. 
Compatibility
You can use $gt for deployments hosted in the following environments:
- MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud 
- MongoDB Enterprise: The subscription-based, self-managed version of MongoDB 
- MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB 
Syntax
The $gt operator has the following form:
{ field: { $gt: value } } 
Examples
The following examples use the inventory collection. Create the collection:
db.inventory.insertMany( [  {  item: "nuts", quantity: 30,  carrier: { name: "Shipit", fee: 3 }  },  {  item: "bolts", quantity: 50,  carrier: { name: "Shipit", fee: 4 }  },  {  item: "washers", quantity: 10,  carrier: { name: "Shipit", fee: 1 }  } ] ) 
Match Document Fields
Select all documents in the inventory collection where quantity is greater than 20:
db.inventory.find( { quantity: { $gt: 20 } } ) 
Example output:
{  _id: ObjectId("61ba25cbfe687fce2f042414"),  item: 'nuts',  quantity: 30,  carrier: { name: 'Shipit', fee: 3 } }, {  _id: ObjectId("61ba25cbfe687fce2f042415"),  item: 'bolts',  quantity: 50,  carrier: { name: 'Shipit', fee: 4 } } 
Perform an Update Based on Embedded Document Fields
The following example sets the price field based on a $gt comparison against a field in an embedded document.
db.inventory.updateOne(  { "carrier.fee": { $gt: 2 } }, { $set: { "price": 9.99 } } ) 
Example output:
{  _id: ObjectId("61ba3ec9fe687fce2f042417"),  item: 'nuts',  quantity: 30,  carrier: { name: 'Shipit', fee: 3 },  price: 9.99 }, {  _id: ObjectId("61ba3ec9fe687fce2f042418"),  item: 'bolts',  quantity: 50,  carrier: { name: 'Shipit', fee: 4 } }, {  _id: ObjectId("61ba3ec9fe687fce2f042419"),  item: 'washers',  quantity: 10,  carrier: { name: 'Shipit', fee: 1 } } 
This updateOne() operation searches for an embedded document, carrier, with a subfield named fee. It sets { price: 9.99 } in the first document it finds where fee has a value greater than 2.
To set the value of the price field in all documents where carrier.fee is greater than 2, use updateMany().