If you have a MongoDB collection with dates stored as strings, you can convert those into the Date BSON type if required.
Below are three ways to convert a string into a Date in MongoDB.
Continue readingCategory: MongoDB
Remove Duplicates when using $unionWith in MongoDB
In MongoDB, the $unionWith aggregation pipeline stage performs a union of two collections, and it includes duplicates.
This behaves in a similar way to SQL’s UNION ALL, which also includes duplicates. By contrast, using just UNION (i.e. without the ALL)in SQL removes duplicates.
In MongoDB, we don’t have the option of specifying $unionWith ALL or similar, so we need to reduce duplicates in another way.
In MongoDB, we can remove duplicates by using the $group stage.
3 Ways to Return a Random Sample of Documents from a MongoDB Collection
If you need to return a small sample of random documents from a collection, here are three approaches you can try using the aggregation pipeline.
Continue readingMongoDB Aggregation Operators for Returning Date Parts
This article lists the various aggregation pipeline operators that can be used to return individual date parts from a Date object in MongoDB.
Continue reading2 Ways to Unhide an Index in MongoDB
If you have a hidden index in MongoDB, you can use the unhideIndex() method or the collMod administration command to unhide it.
MongoDB $round vs $trunc: What’s the Difference?
MongoDB’s aggregation pipeline framework includes a $round operator and a $trunc operator. These operators perform similar, but different tasks.
$strLenBytes vs $strLenCP in MongoDB: What’s the Difference?
MongoDB includes the $strLenBytes and $strLenCP operators in its aggregation pipeline framework. These operators do a similar but slightly different thing. In some cases, both will return exactly the same result, while in other cases the results will differ.
Here’s a quick overview of the difference between these two operators.
Continue reading2 Ways to Get a Document’s Size in MongoDB
If you need to return the size of a document in MongoDB, you can use the following:
- The
$bsonSizeaggregation pipeline operator - The
Object.bsonSize()method
Below are examples of each approach.
Continue reading3 Ways to Sort Documents in MongoDB
MongoDB provides a few ways to sort documents in a particular order. Each of these allow us to order the documents in ascending or descending order.
There’s also the option to order the results of a $text search – sorting by the computed textScore metadata in descending order.
Here are 3 ways to sort documents in MongoDB.
Continue reading3 Ways to Convert a Date to a String in MongoDB
MongoDB has a Date BSON type that allows you to store dates as dates.
You can also store dates as strings, if that’s what you need.
Taking it a step further, you can also convert a Date to a string.
This article presents three ways to convert a Date to a string in MongoDB.
Continue reading