mongodb查询

更多时间：2014-12-15 类别：数据库浏览量：1345

mongodb查询

mongodb查询

一、基本查询

1、如果有如下一条记录，用findOne可以查找


> db.test.findOne()
    {
         "_id" : ObjectId("4fd58ecbb9ac507e96276f1a"),
         "name" : "stephen",
         "age" : 35,
         "genda" : "male",
         "email" : ""
    }

2、返回指定的文档键值对。下面的示例将只是返回name和age键值对

> db.test.find({}, {"name":1,"age":1})
{ "_id" : ObjectId("4fd58ecbb9ac507e96276f1a"), "name" : "stephen", "age" : 35 }

3、指定不返回的文档键值对。下面的示例将返回除name之外的所有键值对

> db.test.find({}, {"name":0})
{ "_id" : ObjectId("4fd58ecbb9ac507e96276f1a"), "age" : 35, "genda" : "male", "email" : "" }

二、查询条件

MongoDB提供了一组比较操作符：$lt/$lte/$gt/$gte/$ne，依次等价于</<=/>/>=/!=。

1、返回符合条件age >= 18 && age <= 40的文档

> db.test.find({"age":{"$gte":18, "$lte":40}})

2、返回条件符合name != "stephen1"

> db.test.find({"name":{"$ne":"stephen1"}})

3、$in等同于SQL中的in，下面的示例等同于SQL中的in ("stephen","stephen1")

> db.test.find({"name":{"$in":["stephen","stephen1"]}})

4、和SQL不同的是，MongoDB的in list中的数据可以是不同类型。这种情况可用于不同类型的别名场景

> db.test.find({"name":{"$in":["stephen",123]}})

5、$nin等同于SQL中的not in，同时也是$in的取反

> db.test.find({"name":{"$nin":["stephen2","stephen1"]}})

6、$or等同于SQL中的or，$or所针对的条件被放到一个数组中，每个数组元素表示or的一个条件。下面的示例等同于name = "stephen1" or age = 35

> db.test.find({"$or": [{"name":"stephen1"}, {"age":35}]})

7、混合使用$or和$in

> db.test.find({"$or": [{"name":{"$in":["stephen","stephen1"]}}, {"age":36}]})

8、$not表示取反，等同于SQL中的not

> db.test.find({"name": {"$not": {"$in":["stephen2","stephen1"]}}})

三、limit(),skip(),sort()

测试数据


post1 = {"title":"learn MongoDB", "author":"Wilber", "date":new Date(), "score":90}
post2 = {"title":"learn English", "author":"Will", "date":new Date(), "score":95}
post3 = {"title":"learn C#", "author":"Li", "date":new Date(), "score":80}
post4 = {"title":"learn SQL", "author":"July", "date":new Date(), "score":70}
post5 = {"title":"learn Node", "author":"Wilber", "date":new Date(), "score":93}
db.blog.posts.insert(post1)
db.blog.posts.insert(post2)
db.blog.posts.insert(post3)
db.blog.posts.insert(post4)
db.blog.posts.insert(post5)

users1 = ["Wilber", "Will", "June"]
users2 = ["Will", "July", "Wilber"]
users3 = ["James", "Jack", "Will"]
db.blog.users.insert({"users":users1})
db.blog.users.insert({"users":users2})
db.blog.users.insert({"users":users3})

mongodb查询

SQL 代码复制


> db.blog.posts.find({"author":"Will"})

{ "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "date" : ISODate("2014-11-
29T13:28:17.959Z"), "score" : 95 }

> db.blog.posts.find({}, {"title":1, "score":1})

{ "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "score" : 90 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "score" : 95 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "score" : 80 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "score" : 70 }
{ "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "score" : 93 }

> db.blog.posts.find({}, {"date": 0})

{ "_id" : ObjectId("5479c9f2421b7f1536cfb207"), "title" : "learn MongoDB", "author" : "Wilber", "score" : 90 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb208"), "title" : "learn English", "author" : "Will", "score" : 95 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb209"), "title" : "learn C#", "author" : "Li", "score" : 80 }
{ "_id" : ObjectId("5479c9f2421b7f1536cfb20a"), "title" : "learn SQL", "author" : "July", "score" : 70 }
{ "_id" : ObjectId("5479c9f4421b7f1536cfb20b"), "title" : "learn Node", "author" : "Wilber", "score" : 93 }

四、null数据类型的查询

1、在进行值为null数据的查询时，所有值为null，以及不包含指定键的文档均会被检索出来

例如



			
				> db.test.find({"x":null})
			
				 { "_id" : ObjectId("4fd59d30b9ac507e96276f1b"), "x" : null }  { "_id" : ObjectId("4fd59d49b9ac507e96276f1c"), "y" : 1 }

2、查询集合c中y的值为null，（仅返回y的值为null的数据，不会返回不存在的）

>db.c.find( { “y” : { $type : 10 } } )

还有一种写法如下

>db.c.find({“y”:{“$in”:[null], “$exists”:true}})

3、查询集合c中y的值不存在（不会返回y的值为null的数据）

>db.c.find( { “y” : { $exists : false } } )

四、正则查询

MongoDB中使用了Perl规则的正则语法

> db.test.find({"name":/stephen?/i})

			
				 { "_id" : ObjectId("4fd59ed7b9ac507e96276f1d"), "name" : "stephen" } 
			
				     { "_id" : ObjectId("4fd59edbb9ac507e96276f1e"), "name" : "stephen1" }

五、基于数组的查找

例如，有如下数据

{ "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", "peach" ] }

{ "_id" : ObjectId("4fd5a18cb9ac507e96276f20"), "fruit" : [ "apple", "kumquat","orange" ] }

{ "_id" : ObjectId("4fd5a1f0b9ac507e96276f21"), "fruit" : [ "cherry", "banana","apple" ] }

1、数组中所有包含banana的文档都会被检索出来



			
				> db.test.find({"fruit":"banana"})
			
				 { "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", "peach" ] } 
			
				 { "_id" : ObjectId("4fd5a1f0b9ac507e96276f21"), "fruit" : [ "cherry", "banana","apple" ] }

2、检索数组中需要包含多个元素的情况，这里使用$all。下面的示例中，数组中必须同时包含apple和banana，但是他们的顺序无关紧要


 > db.test.find({"fruit": {"$all": ["banana","apple"]}})

			
				 { "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", "peach" ] } 
			
				 { "_id" : ObjectId("4fd5a1f0b9ac507e96276f21"), "fruit" : [ "cherry", "banana", "apple" ] }

3、下面的示例表示精确匹配，即被检索出来的文档，fruit值中的数组数据必须和查询条件完全匹配，即不能多，也不能少，顺序也必须保持一致


> db.test.find({"fruit":["apple","banana","peach"]})

			
				 { "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", peach" ] }

4、下面的示例将匹配数组中指定下标元素的值。数组的起始下标是0


> db.test.find({"fruit.2":"peach"})

			
				 { "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", peach" ] }

5、可以通过$size获取数组的长度，但是$size不能和比较操作符联合使用



			
				> db.test.find({"fruit": {$size : 3}})
			
				 { "_id" : ObjectId("4fd5a177b9ac507e96276f1f"), "fruit" : [ "apple", "banana", "peach" ] }
			
				 { "_id" : ObjectId("4fd5a18cb9ac507e96276f20"), "fruit" : [ "apple", "kumquat","orange" ] }
			
				 { "_id" : ObjectId("4fd5a1f0b9ac507e96276f21"), "fruit" : [ "cherry", "banana","apple" ] }

标签：mongodb

上一篇：asp.net MVC处理流程

下一篇：mongodb用户权限

您可能感兴趣

mongodb查询

mongodb查询

热门推荐

排行榜