MongoDB Query Documents
MongoDB Query Documents – db.inventory.find(criteria) is used to query all MongoDB Documents, or filter them based on a criteria, from a MongoDB Collection.
Examples
- Query All Documents in a Collection
- Query Documents of a MongoDB Collection based on a Criteria
Example 1 – Query All Documents in a Collection
To query all documents in a collection, use find() method with empty document as argument.
Following is the syntax of find command to query all documents
db.<collection>.find( {} )<collection> is the name of the MongoDB Collection.
Following command queries all documents in people collection present intutorialkart database
> use tutorialkart
switched to db tutorialkart
> db.people.find({})
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb2"), "name" : "Midhuna", "age" : 23, "place" : "Amaravati" }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb3"), "name" : "Akhil", "age" : 24, "place" : "New York", "bonus" : 250 }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb4"), "name" : "Honey", "age" : 27, "profession" : "Docter" }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb5"), "name" : "Manju", "age" : 28, "place" : "Vizag", "profession" : "Driver" }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb6"), "name" : "Bharat", "age" : 24, "place" : "New York", "profession" : "Programmer", "bonus" : 250 }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb7"), "name" : "Arya", "age" : 25, "profession" : "Teacher" }
Example 2 – Query Documents of a Collection based on a Criteria
Following example demonstrates to query those documents of a Collection that respect a criteria.
Select the database in which the collection is, using USE command.
> use tutorialkart
switched to db tutorialkart
Prepare a criteria to select documents
> criteria={place:"New York"}
{ "place" : "New York" }
Use the criteria with find() method to select those documents that obey the criteria.
> criteria={name:"Manju"}
{ "name" : "Manju" }
Run find(criteria) method
> db.people.find(criteria)
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb3"), "name" : "Akhil", "age" : 24, "place" : "New York", "bonus" : 250 }
{ "_id" : ObjectId("59eeba4e5f82df4555f2bfb6"), "name" : "Bharat", "age" : 24, "place" : "New York", "profession" : "Programmer", "bonus" : 250 }
Conclusion
In this MongoDB Tutorial – MongoDB Query Documents db.inventory.find(criteria) is used to query all MongoDB Documents, or filter them based on a criteria, from a MongoDB Collection.