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"sport": "NFL","team_id": 5,"week_num": 6,"meta": { .... more data ...., "season_year": 2013}变为"sport": "NFL","team_id": 5,"week_num&q

> db.users.findOne(){ "_id" : ObjectId("51e3e2e16a847147f7ccdf7d"), "user" : "testAdmin", "pwd" : "[some hash]", "roles" : [ "clusterAdmin&quo

{ "$project" : { 'totalA' : '$totalA', 'totalB' : '$totalB', 'totalSum' : { '$add' : [ '$totalA', '$totalB' ] }, } 

{ $cond: [ <boolean-expression>, <true-case>, <false-case> ] }db.activity.insert({"userUrl": "http://news.bbc.co.uk", "userAddress" : "1.2.3.4", "requestTime" :

{ students: [ { name: "john", school: 102, age: 4 }, { name: "jess", school: 102, age: 11 }, { name: "jeff", school: 108, age: 7 } ]}{...

if amount < 0, then 0 - amount  else { $project: { amount: { $cond: [ { $lt: ['$amount', 0] }, { $subtract: [0, '$amount'] }, '$amount' ]}}} 

{ attrib : [ { k: "color", v: "red" }, { k: "shape", v: "rectangle" }, { k: "color", v: "blue" }, { k: "avail", v: true } ]}统计 color

db.collection.remove( { _id : { $in: [ ObjectId("51ee3966e4b056fe8f074f48"), ObjectId("51ee3966e4b056fe8f074f4a"), ObjectId("51ee3966e4b056fe8f074f4b") ] } } ); 

{queid:'1',date:'07023/2013',topic: 'topic1'}{queid:'2',date:'07022/2013',topic: 'topic2'}{queid:'3',date:'07022/2013',topic: 'topic1'}{queid:'4',date:'07023/2013',topic: 'topic1'}que.agg...

{ num: 4, title: "alpha", data: 7538 }{ num: 2, title: "beta", data: 7538 }{ num: 7, title: "beta", data: 7538 }{ num: 5, title: "alpha", data: 7538 }希望{ num: 2, title: "beta", data: 7538...

{ "_id" : ObjectId("5188c93f0361ca6dc33e3a30"), "admin" : [ ], "created" : "2013-04-30 19:10:21", "description" : "guitar theory", "mem

db.images.distinct( "gallery" , { "gallery" : { $nin : ["", null] } }); 

{ "_id" : ObjectId("515d8f53175b8ecb053425c2"), "category" : "Batteries", "products" : [ { "brand" : "Duracell", "item" : [

SELECT COUNT(*), SUM(PKTS), SUM(BYTES) FROM mytableSELECT srcad, srcpo, dstad, dstpo, pro, COUNT(*), SUM(PKTS), SUM(BYTES) FROM mytable WHERE scrpo=80 OR dstpo=80 GROUP BY srcad, scrpo, dstad, d...

预先占位在一个额外的字段，然后取消comments = [ {name : "Name Surname", date : "1970.01.01", text : "this is a placeholder"}, {name : "Name Surname", date : "1970.01.01", text : "this is a placeholder&q

SELECT * FROM testWHERE (name LIKE '%star%' AND NOT name LIKE '%trek%') OR duration = 200db.test.find({$or: [ { name: /star/i, name: { $not: /trek/i } }, { duration: 200 } ...

{ _id: 1, name: 'John Smith', items: [{ id: 1, name: 'item 1', value: 'one' },{ id: 2, name: 'item 2', value: 'two' }]}Person.update({'items.i...

case1 OR ( [case2 AND case3] OR [case4 AND case5] )You can try to use the $or operator:db.hg19_refgene_47.find({ $or: [ "_id.c" : 1, { "_id.p" : {"$gte" : 96978}, ...

if (doc.timestampField < older) { collection.remove(doc); } }) var older=Date.parse("2013-03-01"), all=collection.find();all.forEach(function(doc) { var ts = doc._id.getTimestamp(); if ...

{ "_id" : ObjectId("51596b7e469b9c3816000001"), "company" : { "_id" : "ade2fd0ec9b8b5e9152e0155", "title" : "LO3426546457" }

db.collection.find().limit(100).forEach(function(doc) { db.collection.remove({_id:doc._id});}); 

{ "_id": { "$id": "515bb7e2a00b2add0b000001" }, "user_id": "user_8888", "events": { "common test I": { "subject": "comm

{ account:"abc", vendor:"amazon",} ...{ account:"abc", vendor:"overstock",}想得到{ account:"abc", vendorCount:2}b.collection.aggregate([{ $group: { _id: { account: '...