How to use Aggregation Pipeline In MongoDB
The aggregation pipeline in MongoDB allows us to process data from a collection and perform various operations, such as filtering, grouping, sorting, and transforming documents. It consists of a series of stages, where each stage performs a specific operation on the data.
Syntax:
db.collection.aggregate([
{ $stage1: { <stage1-operator>: <expression> } },
{ $stage2: { <stage2-operator>: <expression> } },
// Add more stages as needed
])
Example:
db.students.aggregate({$match:{"subjects.3":{$exists:true}}})
Output:
using aggregation pipeline
Explanation: The above query searched for all the documents whose “subjects” field has size greater than “3”.
How to Query for Documents Where Array Size is Greater Than 1 in MongoDB
MongoDB’s flexibility extends to handling arrays within documents, making it a powerful choice for data storage in modern applications. One common requirement is to find documents where an array field contains more than one element.
In this article, We will various methods through which we can easily find the size of an array that is greater than 1.