Marc questions

Marc answers

• Querying directly on results from MongoDB mapreduce versus updating original collection
• How to import only non existing documents?
• Removing from Mongo old documents by id
• MongoDB - $unwind - how to unwind more than one array in a $group aggregation
• How to change the structure of MongoDB's map-reduce results?
• MongoDB Update Deep Array
• MongoDB sorted geo bounding box
• Mongo {$ne : null} not working as expected
• MongoDB - Import CSV into nested document
• How to join MongoDB collections in Python?