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MongoDB: How to construct a query in mongoDB when selection of documents have "OR" based condition ?

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MongoDB: How to construct a query in mongoDB when selection of documents have "OR" based condition ?
posted Jun 28, 2015 by Vikram Singh

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1 Answer

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This is a very general query and used day to day basis.
I will explain this by using an example.
A database has a number of collections and a particular collection has documents as following:

{ "_id" : ObjectId("1"), "key1" : 1 }
{ "_id" : ObjectId("2"), "key4" : 1 }
{ "_id" : ObjectId("3"), "key4" : 1 }
{ "_id" : ObjectId("4"), "key4" : 1 }
{ "_id" : ObjectId("5"), "key4" : 1 }
{ "_id" : ObjectId("6"), "key4" : 1 }
{ "_id" : ObjectId("7"), "key4" : 1 }
{ "_id" : ObjectId("8"), "key5" : 1 }

Each row holds data of one document. Now a user want to get the list of documents which have either key1 or key5 fields.
db.secondCollection.find({$or : [{key1:1}, {key5:1}]})

The query constructed above gives the following result.

{ "_id" : ObjectId("1"), "key1" : 1 }
{ "_id" : ObjectId("8"), "key5" : 1 }

I answered your query hope so. If you still have any doubt then please ask.

answer Jun 28, 2015 by Harshita
Harshita, Thanks a lot for your quick response.
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