MongoDB简单使用-查询操作3

首先添加几个文档：

dvd = ({"Type":"DVD","Title":"Matrix,The","Released":1994,"Cast":["Keanu Reeves","Carrie-Anne Moss","Laurence Fishburne","Hugo Weaving","Gloria Foster","Joe Pantoliano"]})

db.media.insertOne(dvd)

dvd = ({"Type":"DVD","Title":"Blade Runner","Released":1982})
db.media.insertOne(dvd)

dvd = ({"Type":"DVD","Title":"Toy Story 3","Released":2010})

db.media.insertOne(dvd)

1.比较符号（$gt,$gte,$lt,$lte) #（大于，大于等于，小于，小于等于）

db.media.find({Released:{$gt:2000}},{"Cast":0})

系统返回
{ "_id" : ObjectId("5aa4984153350e04ddbd6fab"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 }

db.media.find({Released:{$gte:1994,$lt:2010}},{"Cast":0})

系统返回
{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994 }

2.$in,$all,$or

db.media.find({Released:{$in:[1994,2008,2009]}},{"Cast":0}

系统返回

{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994 }

db.media.find({Released:{$all:[1994,2008,2009]}},{"Cast":0})

系统返回

（又不存在同时满足3个条件的文档，返回空）

db.media.find({$or:[{"Title":"Toy Story 3"},{"ISBN":"978-1-4842-1183-0"}]})

系统返回
{ "_id" : ObjectId("5aa490f053350e04ddbd6fa6"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB 3rd ed.", "ISBN" : "978-1-4842-1183-0", "Publisher" : "Apress", "Author" : [ "Hows,David", "Plugge,Eelco", "Membrey,Peter", "Hawkins,Tim" ] }

3.$slice

db.media.find({"Title":"Matrix,The"},{"Cast":{$slice:3}})

系统返回
{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994, "Cast" : [ "Keanu Reeves", "Carrie-Anne Moss", "Laurence Fishburne" ] }

db.media.find({"Title":"Matrix,The"},{"Cast":{$slice:[-5,4]}}) #从最后5项中截取前4个

系统返回
{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994, "Cast" : [ "Carrie-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster" ] }

4.$mod

db.media.find({Released:{$mod:[3,2]}},{"Cast":0})

系统返回：

{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994 }
{ "_id" : ObjectId("5aa4981653350e04ddbd6faa"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }

5.$size

db.media.find({Tracklist:{$size:2}})

6.$exists

db.media.find({Author:{$exists:true}})

系统返回：
{ "_id" : ObjectId("5aa490f053350e04ddbd6fa6"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB 3rd ed.", "ISBN" : "978-1-4842-1183-0", "Publisher" : "Apress", "Author" : [ "Hows,David", "Plugge,Eelco", "Membrey,Peter", "Hawkins,Tim" ] }
{ "_id" : ObjectId("5aa4915453350e04ddbd6fa8"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB 3rd ed.", "ISBN" : "978-1-4842-1183-1", "Publisher" : "Apress", "Author" : [ "Hows,David", "Plugge,Eelco", "Membrey,Peter", "Hawkins,Tim" ] }

db.media.find({Author:{$exists:false}})

系统返回：
{ "_id" : ObjectId("5aa4912953350e04ddbd6fa7"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }
{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994, "Cast" : [ "Keanu Reeves", "Carrie-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] }
{ "_id" : ObjectId("5aa4981653350e04ddbd6faa"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }
{ "_id" : ObjectId("5aa4984153350e04ddbd6fab"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 }

7.$type

db.media.find({Tracklist:{$type:3}}) #type：3表示嵌入式对象
{ "_id" : ObjectId("5aa4912953350e04ddbd6fa7"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }

8.$elemMatch

db.media.find({"Tracklist.Title":"Smells Like Teen Spirit","Tracklist.Track":"1"})

系统返回：
{ "_id" : ObjectId("5aa4912953350e04ddbd6fa7"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }
{ "_id" : ObjectId("5aa49fe653350e04ddbd6fac"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nirvana", "Tracklist" : [ { "Track" : "1", "Title" : "You Know You Are Right", "Length" : "3:38" }, { "Track" : "5", "Title" : "Smells Like Teen Spirit", "Length" : "5:02" } ] }

db.media.find({Tracklist:{$elemMatch:{Title:"Smells Like Teen Spirit",Track:"1"}}})

9.正则表达式

db.media.find({Title:/^Matrix*/i}) #i表示不区分大小写

系统返回：
{ "_id" : ObjectId("5aa497c753350e04ddbd6fa9"), "Type" : "DVD", "Title" : "Matrix,The", "Released" : 1994, "Cast" : [ "Keanu Reeves", "Carrie-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] }