Scalar Functions

• Description: Converts a string to upper or lower case respectively.
• Example (MongoDB using $toUpper and $toLower in aggregation):

db.names.aggregate([{$project: {nameUpper: {$toUpper: "$name"}, nameLower: {$toLower: "$name"}}}]);

Converts the name field of each document to upper and lower case.

• Description: Returns the length of a string.
• Example (MongoDB) :

db.names.aggregate([{$project: {nameLength: {$strLenCP: "$name"}}}]);

Calculates the length of the name field for each document.

• Description: Rounds a number to the nearest integer or specified decimal place.
• Example (MongoDB) :

db.finances.aggregate([{$project: {roundedValue: {$round: ["$amount", 2]}}}]);

Rounds the amount field to two decimal places.