Table of Contents
How does a compound query work in MongoDB?
If the compound query conditions on an array field do not use the $elemMatch operator, the query selects those documents whose array contains any combination of elements that satisfies the conditions.
How to join data from user collection in MongoDB?
We can now join data from the user collection using the new $lookup operator. It requires an object with four parameters: as: the name of the output field. This will create a new field in our output named userinfo. It contains an array where each value is the matching the user document:
How to merge two array fields in MongoDB?
Merge two array fields in MongoDB? MongoDB order by two fields sum? MongoDB aggregation to combine or merge fields and then count? MongoDB query condition to compare two fields? Select two fields and return a sorted array with their distinct values in MongoDB? Find sum of fields inside array in MongoDB?
How to query an array in MongoDB Java?
To populate the inventory collection, run the following: This page provides examples of query operations on array fields using the com.mongodb.client.MongoCollection.find method in the MongoDB Java Synchronous Driver. The driver provides com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents.
If the compound query conditions on an array field do not use the $elemMatch operator, the query selects those documents whose array contains any combination of elements that satisfies the conditions.
We can now join data from the user collection using the new $lookup operator. It requires an object with four parameters: as: the name of the output field. This will create a new field in our output named userinfo. It contains an array where each value is the matching the user document:
To populate the inventory collection, run the following: This page provides examples of query operations on array fields using the com.mongodb.client.MongoCollection.find method in the MongoDB Java Synchronous Driver. The driver provides com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents.
Merge two array fields in MongoDB? MongoDB order by two fields sum? MongoDB aggregation to combine or merge fields and then count? MongoDB query condition to compare two fields? Select two fields and return a sorted array with their distinct values in MongoDB? Find sum of fields inside array in MongoDB?
How to query an array of nested documents in MongoDB?
This page provides examples of query operations on an array of nested documents using the com.mongodb.client.MongoCollection.find method in the MongoDB Java Synchronous Driver. The driver provides com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents.
How to query the dim _ cm array in MongoDB?
The following example queries for documents where the dim_cm array contains elements that in some combination satisfy the query conditions; e.g., one element can satisfy the greater than 15 condition and another element can satisfy the less than 20 condition, or a single element can satisfy both:
How to specify equality for an array in MongoDB?
To specify equality condition on an array, use the query document eq( <field>, <value>) where <value> is the exact array to match, including the order of the elements. To specify equality condition on an array, use the query document { <field>: <value> } where <value> is the exact array to match, including the order of the elements.
This page provides examples of query operations on an array of nested documents using the com.mongodb.client.MongoCollection.find method in the MongoDB Java Synchronous Driver. The driver provides com.mongodb.client.model.Filters helper methods to facilitate the creation of filter documents.
How does the return array work in MongoDB?
New in version 3.4.4. Converts a document to an array. The return array contains an element for each field/value pair in the original document. Each element in the return array is a document that contains two fields k and v: The k field contains the field name in the original document.
To specify equality condition on an array, use the query document eq( , ) where is the exact array to match, including the order of the elements. To specify equality condition on an array, use the query document { : } where is the exact array to match, including the order of the elements.
The following example queries for documents where the dim_cm array contains elements that in some combination satisfy the query conditions; e.g., one element can satisfy the greater than 15 condition and another element can satisfy the less than 20 condition, or a single element can satisfy both: