1
我正在使用mongoDB 2.6.5。我有一本藏書。如何在MongoDB中獲得不同的結果?
> db.books.find()
{ "_id" : "5476f8b5e4b04367d6c95010", "author" : "abc", "title" : "xyz", "isbnNo" : "9781887902991", "category" : "Computer" }
{ "_id" : "5476fae0e4b0016adffd08e4", "author" : "bcd", "title" : "uvw", "isbnNo" : "9781887902991", "category" : "Computer" }
{ "_id" : "5476fb7ce4b0016adffd08e5", "author" : "cde", "title" : "pqr", "isbnNo" : "9781887902991", "category" : "Biography" }
我想結果爲:
{ "_id" : "5476fae0e4b0016adffd08e4", "author" : "bcd", "title" : "uvw", "isbnNo" : "9781887902991", "category" : "Computer" }
{ "_id" : "5476fb7ce4b0016adffd08e5", "author" : "cde", "title" : "pqr", "isbnNo" : "9781887902991", "category" : "Biography" }
我的意思是,從每個類別像MySQL的「組按類別」任何一本書。
我該如何做到這一點?
在此先感謝。