MongoDB Query Document

Question

I have a MongoDB Collection such as the Given Below

{ "IslamabadICT": { "campus_name": "Islamabad", "campus_province": "ICT" }, "KarachiSindh": { "campus_name": "Karachi", "campus_province": "Sindh" }, "LahorePunjab": { "campus_name": "Lahore", "campus_province": "Punjab" }, "PeshawarKPK": { "campus_name": "Peshawar", "campus_province": "KPK" } }

and I want to Query all the documents where campus_name='Lahore'. I'm running the following command

db.campus.find({"campus_name":"Lahore"}).pretty() but it returns nothing. The version of MondoDB is 3.4 and I'm running mongo shell.

Any suggestions ?

Thanks in Advance

Try this db.campus.find({"LahorePunjab.campus_name":"Lahore"}).pretty() — Neo-coder
– Neo-coder, Commented May 18, 2017 at 15:29
@Yogesh, that will not search for campus_name only, it'll first try to find the LahorePunjab field in document and If that fails it'll simply ignore the campus_name field value. — Mukesh Saini
– Mukesh Saini, Commented May 18, 2017 at 15:36

Mukesh Saini · Accepted Answer · 2017-05-18 15:38:23Z

Here is the query that will return the document where campus_name='Lahore' -

db.campus.find().map( function(myDoc) { for (var key in myDoc) { if(key != "_id" && myDoc[key].campus_name == "Lahore"){ print( "Found it!!"); return myDoc; } } return null; } ).find(function(doc){if(doc!=null) return doc;});

Apart from this, I would highly recommend you to restructure your document format. One example could be to restructure the documents as follows -

{ { "main": "IslamabadICT", "campus_name": "Islamabad", "campus_province": "ICT" }, { "main": "KarachiSindh", "campus_name": "Karachi", "campus_province": "Sindh" }, { "main": "LahorePunjab", "campus_name": "Lahore", "campus_province": "Punjab" }, { "main": "PeshawarKPK", "campus_name": "Peshawar", "campus_province": "KPK" } }

It will make the query a lot easier -

db.sht.find({campus_name:"Lahore"}).pretty()

Which is the one you tried in first place. :)

thanks.....I changed the format of my Collection, it's working well now

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