In this post, we will learn How to query for Distinct values in Mongoose where we can implement the same using a built in function district which returns an array as the result of different values for each and every specific field in the collection.
Distinct Value
As we can use the different function to get the values of different values stored in the collection. and to implement the same we have given an example below where we can implement to get all the different values in a field and solve the problem of duplications here in a particular field.
const MyModel = require('C:\Program Files\MongoDB\Server\6.0\bin');
// Find all different values for the 'fieldName' field in the collection
MyModel. distinct(' field name, function( err, results) {
if ( err) throw err;
console.log( results);
});
In the example given above code, you need to make certain changes before using it in your project as the name of particular variables and all need to get changes as per your project. where ‘fieldName’ with the name of the field for which you want to find different values. The district method returns an array of different value values for that field. we can also add an additional query method in that to refine the result as per our choice.
MyModel.distinct(' fieldName').where(' otherField'). equals(' someValue'). exec( function( err, results) {
if ( err) throw err;
console. log( results);
});
In the example given above where a clause is used for making more filters to the result, we are getting.
We can implement the same function by following the way we have given below.
const MyModel = require('C:\Program Files\MongoDB\Server\6.0\bin');
MyModel. distinct(' field name).then(results => {
console.log(results);
}).catch(err => {
console. error(err);
});
The code given above will also give the same result but here we had adopted a different approach to get the task done. Here we can also pass a query object as the first parameter to the distinct() method with an argument to filter the documents before finding different values and the example for the same is given below.
MyModel.distinct('fieldName', { age: { $gt: 30 } }).then(results => {
console.log( results);
}).catch(err => {
console.error( err);
});
Here we added another filter above 30 which simply means it will make difference only to those where the age is greater than 30.
To learn more about How do I query for different values in Mongoose visit: How do I query for different values in Mongoose?.
To learn more about MongoDB solutions to different problems faced in MongoDB along with concepts and tutorials one different topic visit: MongoDB Problems And Tutorials.
