How to limit the amount of characters returned from a field in a MongoDB?

To limit the amount of characters returned from a field, use $substr in MongoDB. Let us create a collection with documents −

> db.demo233.insertOne({"Paragraph":"My Name is John Smith.I am learning MongoDB database"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e41877df4cebbeaebec5146") } > db.demo233.insertOne({"Paragraph":"David Miller is a good student and learning Spring and Hibernate Framework."}); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4187d7f4cebbeaebec5147") }

Display all documents from a collection with the help of find() method −

> db.demo233.find().pretty();

This will produce the following output −

{    "_id" : ObjectId("5e41877df4cebbeaebec5146"),    "Paragraph" : "My Name is John Smith.I am learning MongoDB database" } {    "_id" : ObjectId("5e4187d7f4cebbeaebec5147"),    "Paragraph" : "David Miller is a good student and learning Spring and Hibernate Framework." }

Following is the query to limit the amount of characters returned from a field in MongoDB −

> db.demo233.aggregate( ...   [ ...      { ...         $project: ...         { ...            Paragraph: { $substr: [ "$Paragraph", 0, 10] } ... ...      } ...} ] )

This will produce the following output −

{ "_id" : ObjectId("5e41877df4cebbeaebec5146"), "Paragraph" : "My Name is" } { "_id" : ObjectId("5e4187d7f4cebbeaebec5147"), "Paragraph" : "David Mill" }