Posted on 16 Aug 2022, this text provides information on Bugs & Fixes related to General Tech. Please note that while accuracy is prioritized, the data presented might not be entirely correct or up-to-date. This information is offered for general knowledge and informational purposes only, and should not be considered as a substitute for professional advice.
Note that this does not update your collection but instead replace the existing collection or create a new one. Also for update operations that require "type casting" you will need client side processing, and depending on the operation, you may need to use the find() method instead of the .aggreate() method.
MongoDB 3.2 and 3.0
The way we do this is by $projecting our documents and use the $concat string aggregation operator to return the concatenated string. we From there, you then iterate the cursor and use the $set update operator to add the new field to your documents using bulk operations for maximum efficiency.
Aggregation query:
var cursor = db.collection.aggregate([{"$project":{"name":{"$concat":["$firstName"," ","$lastName"]}}}])
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manpreet
Best Answer
2 years ago
In MongoDB, is it possible to update the value of a field using the value from another field? The equivalent SQL would be something like:
And the MongoDB pseudo-code would be: