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MongoDB query to find on field combination of FirstName and LastName?
For combination, use $concat and check the equality using $eq. Let us create a collection with documents −
> db.demo502.insertOne({"FirstName":"John","LastName":"Smith"});{ "acknowledged" : true, "insertedId" : ObjectId("5e875534987b6e0e9d18f56d") } > db.demo502.insertOne({"FirstName":"David","LastName":"Miller"});{ "acknowledged" : true, "insertedId" : ObjectId("5e87553e987b6e0e9d18f56e") } > db.demo502.insertOne({"FirstName":"John","LastName":"Doe"});{ "acknowledged" : true, "insertedId" : ObjectId("5e875543987b6e0e9d18f56f") }
Display all documents from a collection with the help of find() method −
> db.demo502.find();
This will produce the following output −
{ "_id" : ObjectId("5e875534987b6e0e9d18f56d"), "FirstName" : "John", "LastName" : "Smith" } { "_id" : ObjectId("5e87553e987b6e0e9d18f56e"), "FirstName" : "David", "LastName" : "Miller" } { "_id" : ObjectId("5e875543987b6e0e9d18f56f"), "FirstName" : "John", "LastName" : "Doe" }
Following is the query to find on field combination −
> db.demo502.aggregate( ... [ ... { "$redact": { ... "$cond": [ ... { "$eq": [ ... { "$concat": [ "$FirstName", " ", "$LastName" ] }, ... "John Doe" ... ]}, ... "$$KEEP", ... "$$PRUNE" ... ] ... }} ... ] ... )
This will produce the following output −
{ "_id" : ObjectId("5e875543987b6e0e9d18f56f"), "FirstName" : "John", "LastName" : "Doe" }
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