接着前一篇文章，下面主要介绍一下MongoDB中常用的find操作。
先打开MongoDB shell，通过下面一组命令插入一些数据。
1 post1 = {"title":"learn MongoDB", "author":"Wilber", "date":new Date(), "score":90} 2 post2 = {"title":"learn English", "author":"Will", "date":new Date(), "score":95} 3 post3 = {"title":"learn C#", "author":"Li", "date":new Date(), "score":80} 4 post4 = {"title":"learn SQL", "author":"July", "date":new Date(), "score":70} 5 post5 = {"title":"learn Node", "author":"Wilber", "date":new Date(), "score":93} 6 db.blog.posts.insert(post1) 7 db.blog.posts.insert(post2) 8 db.blog.posts.insert(post3) 9 db.blog.posts.insert(post4) 10 db.blog.posts.insert(post5) 11 12 users1 = ["Wilber", "Will", "June"] 13 users2 = ["Will", "July", "Wilber"] 14 users3 = ["James", "Jack", "Will"] 15 db.blog.users.insert({"users":users1}) 16 db.blog.users.insert({"users":users2}) 17 db.blog.users.insert({"users":users3})
find（arg1，arg2）简介
find查询会返回一个Collection中文档的子集。关于find的两个参数，arg1表示匹配条件，arg2可以指定要返回的键。
直接上例子，对于arg2，可以通过设置值为0，来控制那些键不要显示
1 > db.blog.posts.find({"author":"Will"}) 2 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 3 29T13:28:17.959Z"), "score" : 95 } 4 > db.blog.posts.find({}, {"title":1, "score":1}) 5 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "score" : 90 } 6 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "score" : 95 } 7 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "score" : 80 } 8 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "score" : 70 } 9 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "score" : 93 } 10 > db.blog.posts.find({}, {"date": 0}) 11 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "score" : 90 } 12 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "score" : 95 } 13 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "score" : 80 } 14 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "score" : 70 } 15 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "score" : 93 }
常用查询条件
比较条件：$gt,$gte,$lt,$lte,$ne
1 > db.blog.posts.find({"score":{"$gte":90,"$lt":95}}) 2 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 3 1-29T13:28:17.939Z"), "score" : 90 } 4 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 5 9T13:28:17.999Z"), "score" : 93 } 6 > db.blog.posts.find({"author":{"$ne":"July"}}) 7 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 8 1-29T13:28:17.939Z"), "score" : 90 } 9 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 10 29T13:28:17.959Z"), "score" : 95 } 11 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "date" : ISODate("2014-11-29T13:2 12 8:17.979Z"), "score" : 80 } 13 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 14 9T13:28:17.999Z"), "score" : 93 } 15 >
包含条件：$in,$nin
1 > db.blog.posts.find({"author":{"$in":["Wilber","Will"]}}) 2 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 3 1-29T13:28:17.939Z"), "score" : 90 } 4 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 5 29T13:28:17.959Z"), "score" : 95 } 6 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 7 9T13:28:17.999Z"), "score" : 93 } 8 > db.blog.posts.find({"author":{"$nin":["Wilber","Will"]}}) 9 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "date" : ISODate("2014-11-29T13:2 10 8:17.979Z"), "score" : 80 } 11 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "date" : ISODate("2014-11-29T1 12 3:28:17.989Z"), "score" : 70 } 13 >
或操作：$or
1 > db.blog.posts.find({"$or":[{"author":"Wilber"}, {"score":{"$gt":90}}]}) 2 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 3 1-29T13:28:17.939Z"), "score" : 90 } 4 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 5 29T13:28:17.959Z"), "score" : 95 } 6 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 7 9T13:28:17.999Z"), "score" : 93 } 8 >
limit(),skip(),sort()
1 > db.blog.posts.find().limit(2) 2 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 3 1-29T13:28:17.939Z"), "score" : 90 } 4 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 5 29T13:28:17.959Z"), "score" : 95 } 6 > db.blog.posts.find().skip(1) 7 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 8 29T13:28:17.959Z"), "score" : 95 } 9 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "date" : ISODate("2014-11-29T13:2 10 8:17.979Z"), "score" : 80 } 11 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "date" : ISODate("2014-11-29T1 12 3:28:17.989Z"), "score" : 70 } 13 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 14 9T13:28:17.999Z"), "score" : 93 } 15 > db.blog.posts.find().sort({"athor":1,"score":-1}) 16 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 17 29T13:28:17.959Z"), "score" : 95 } 18 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 19 9T13:28:17.999Z"), "score" : 93 } 20 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 21 1-29T13:28:17.939Z"), "score" : 90 } 22 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "date" : ISODate("2014-11-29T13:2 23 8:17.979Z"), "score" : 80 } 24 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "date" : ISODate("2014-11-29T1 25 3:28:17.989Z"), "score" : 70 } 26 >
数组的查询
- $all：通过多个元素匹配数组
- 支持“键.下标”方式的匹配
- 支持$size的方式匹配
1 > db.blog.users.find({"users":"Will"}) 2 { "_id" : ObjectId("5479d03d421b7f1536cfb20c"), "users" : [ "Wilber", "Will", "June" ] } 3 { "_id" : ObjectId("5479d03d421b7f1536cfb20d"), "users" : [ "Will", "July", "Wilber" ] } 4 { "_id" : ObjectId("5479d03d421b7f1536cfb20e"), "users" : [ "James", "Jack", "Will" ] } 5 > db.blog.users.find({"users": {"$all": ["Wilber", "Will"]}}) 6 { "_id" : ObjectId("5479d03d421b7f1536cfb20c"), "users" : [ "Wilber", "Will", "June" ] } 7 { "_id" : ObjectId("5479d03d421b7f1536cfb20d"), "users" : [ "Will", "July", "Wilber" ] } 8 > db.blog.users.find({"users": ["Wilber", "Will"]}) 9 > db.blog.users.find({"users.2":"Will"}) 10 { "_id" : ObjectId("5479d03d421b7f1536cfb20e"), "users" : [ "James", "Jack", "Will" ] } 11 > db.blog.users.find({"users":{"$size":3}}) 12 { "_id" : ObjectId("5479d03d421b7f1536cfb20c"), "users" : [ "Wilber", "Will", "June" ] } 13 { "_id" : ObjectId("5479d03d421b7f1536cfb20d"), "users" : [ "Will", "July", "Wilber" ] } 14 { "_id" : ObjectId("5479d03d421b7f1536cfb20e"), "users" : [ "James", "Jack", "Will" ] } 15 >
null的含义
1 > post5.z = null 2 null 3 > db.blog.posts.update({"title":"learn Node"}, post5) 4 > db.blog.posts.find({"z":null}) 5 { "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "date" : ISODate("2014-1 6 1-29T13:28:17.939Z"), "score" : 90 } 7 { "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11- 8 29T13:28:17.959Z"), "score" : 95 } 9 { "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "date" : ISODate("2014-11-29T13:2 10 8:17.979Z"), "score" : 80 } 11 { "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "date" : ISODate("2014-11-29T1 12 3:28:17.989Z"), "score" : 70 } 13 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 14 9T13:28:17.999Z"), "score" : 93, "z" : null } 15 > db.blog.posts.find({"z":{"$in":[null], "$exists": true}}) 16 { "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "date" : ISODate("2014-11-2 17 9T13:28:17.999Z"), "score" : 93, "z" : null } 18 >
Ps:可以通过以下链接的到例子中的shell命令。
http://files.cnblogs.com/wilber2013/find.js