MongoDb——查询文档

Author：二滑大魔王
发布时间：February 20, 2021
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Categories： DataBase MongoDB

操作符

比较操作符

当在字符串使用gt/lt这种比较操作符时,会查询出字符串首字母按字典排序之后/之前的内容

操作符	query语法	说明
eq	{ <field> : {$eq: <value>} }	等于
ne	{ <field> : {$ne: <value>} }	不等于
gt	{ <field> : {$gt: <value>} }	大于
gte	{ <field> : {$gte: <value>} }	大于等于
lt	{ <field> : {$lt: <value>} }	小于
lte	{ <field> : {$lte: <value>} }	小于等于
in	{ <field> : {$ne: <value>} }	在区间
nin	{ <field> : {$ne: <value>} }	不在区间

逻辑操作符

使用and操作符当条件都为一个字段时可以简写为{<value>: {<experssion1>,<experssion2,...>}}当条件不为一个字段可以简写为{<value1>:<experssion1>,<value2>:<experssion2>,...}

操作符	query语法	说明
not	{ <field>: { $not: {expression} } }	匹配条件不成立的文档
and	{ $and: [{<experssion1>,<expression2>,....}] }	匹配条件全部成立的文档
or	{ $or: [<experssion1>,<experssion2>,...] }	匹配条件至少成立一条的文档
nor	{ $nor: [<experssion1>,<experssion2>,...] }	匹配条件全部不成立的文档

字段操作符

操作符	query语法	说明
exists	{ <field>: { $exists: <bool> } }	匹配字段存在的文档
type	{ <field>: {<fieldType>} } or { <field>: [{<fieldType1>,<fieldType2>}] }	匹配字段符合类型的文档

数组操作符

操作符	query语法	说明
all	{ <field>: [<value>,<value>,...] }	匹配数组字段中包含所有值的文档
elemMatch	{ <field>: {<query1>,<query2>,...} }	匹配字段数组里任意一个元素满足其中的条件即可

运算操作符

操作符	query语法	说明-
$regex	{ <fidld>: { $regex: /patten/ : '<options>'} } 或 { <fidld>: {/patten/ '<options>'} }`(与\$in 使用的时候只能用第二种语法)`	匹配字段满足正则表达式的文档

查询方法

语法

查询命令为:db.<collection>.find(<query>,<projection>).<collection>为要查询的集合名称<projection>为查询的映射,相当于sql中需要查询的字段.

<query>为查询条件其语法为{<field> : {$<op>: <value>}}. 其中<field>为要匹配的字段名.$<op>为匹配符.注意在匹配符前面需要加上$.例如,不等于就应该写作$ne.<value>为匹配值.

示例

查询所有文档的全部字段

# 查询所有文档的全部字段
> db.qvbilam_user.find()

# 返回如下
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

查询姓名为gy的文档

# 查询姓名为gy的文档
> db.qvbilam_user.find({ name: "gy" })

# 返回如下
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }

$gte

- 查询数量大于等于15的文档

# 查询数量大于等于15的文档
> db.qvbilam_user.find({ num: {$gte: 14}  })

# 返回结果
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }

$gt

- 查询姓名大于gy的文档

# 查询姓名大于gy的文档
> db.qvbilam_user.find({ name:{$gt: "gy"} })

# 结果返回 s > g的内容
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$in

- 查询姓名为PEPSI或Coca cola

# 查询姓名为PEPSI或Coca cola
> db.qvbilam_user.find({ name: {$in: ["Coca cola", "PEPSI"]} })

# 返回结果如下
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }

$not, $in

- 查询姓名为PEPSI或Coca cola不成立的结果

# 查询姓名为PEPSI或Coca cola不成立的结果
> db.qvbilam_user.find({ name: {$not: {$in:  ["Coca cola", "PEPSI"]}} })

# 返回结果如下
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$and, $gt,$lte

- 查询数量大于10 并且小于等于13的文档

# 查询数量大于10 并且小于等于13的文档
> db.qvbilam_user.find({
...   $and: [
...     {num: {$gt: 10}},
...     {num: {$lte: 13}}
...   ]
... })

# 返回结果
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$and

- 简写

# 字段相同的情况下and的简写
> db.qvbilam_user.find({
...   num: {$gt:10, $lte:13}
... })

# 字段不通情况下and的简写
> db.qvbilam_user.find({
...   name: {$eq: "gy"},
...   num: {$lte: 13}
... })

$exists

- 查询存在num字段的文档

# 查询存在num字段的文档
> db.qvbilam_user.find({ num: {$exists: true} })

$type

- 查询_id字段类型为string的文档

# 查询_id字段类型为string的文档
> db.qvbilam_user.find({ _id: {$type: "string"} })
# 返回结果
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }

- 查询_id字段类型为string和objectId的文档

# 查询_id字段类型为string和ObjectId的文档
db.qvbilam_user.find({ _id: {$type: ["string","objectId"]} })

$all

- 查询满足所有数组字段的文档

# 创建用户地址数组
> db.qvbilam_user.insert([
...  {
...    name: "MoFan",
...    num: 13,
...    location: ["China","Hebei","ShiJiaZhuang"],
...    mobile: 13211111111
...  },
...  {
...    name: "JunJie",
...    num: 14,
...    location: ["China","ZheJiang","HangZhou"],
...    mobile: 13222222222
...  },
...  {
...    name: "LvKe",
...    num: 15,
...    location: ["China","BeiJing","ChaoYang"],
...    mobile: [13233333333,13244444444,13255555555]
...  }
... ])

# 通过$all查询满足在中国,浙江,杭州的文档
> db.qvbilam_user.find({
...    location: { $all: ["China","ZheJiang","HangZhou"] }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1a"), "name" : "JunJie", "num" : 14, "location" : [ "China", "ZheJiang", "HangZhou" ], "mobile" : 13222222222 }

# 通过$all查询手机号是13233333333,13244444444,13255555555
> db.qvbilam_user.find({
...   mobile: { $all: [[13233333333, 13244444444,13255555555]] }
... })

# 返回
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$elemMatch

- 匹配数组字段至少满足一个值的文档

# 查询手机号在13220000000,13240000000的文档
> db.qvbilam_user.find({
...   mobile: { $elemMatch: { $gt:13211111111, $lte:13240000000} }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$all, $elemMatch

- 满足多个条件的数组

# 查询条件为手机号在13210000000～1322000000之间 同时另一个元素满足 132400000000～13250000000之间的文档
> db.qvbilam_user.find({
...   mobile:{ $all: [
...       {$elemMatch: {$gt: 13230000000,$lt:13240000000}},
...       {$elemMatch: {$gt: 13240000000,$lt:13260000000}}
...       ] }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$regex

第一种写法

# 查询名称包含guo且不区分大小写的文档
db.qvbilam.find({ name: {$regex: /guo/, $options: "i"} })

# 返回
{ "_id" : ObjectId("602f55e24efaa03816f5dbfd"), "name" : "GuoOne", "num" : 15 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfe"), "name" : "GuoTwo", "num" : 20 }
{ "_id" : ObjectId("602f561e4efaa03816f5dbff"), "name" : "GuoThree", "num" : 21 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc00"), "name" : "GuoFour", "num" : 22 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc01"), "name" : "GuoFive", "num" : 25 }

第二种写法

# 查询名称以 a 或 q开偷的文档
db.qvbilam.find({ name: { $in: [/^a/,/^q/] } })

# 返回如下
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55994efaa03816f5dbfc"), "name" : "qvbilam", "num" : 10 }

映射

默认查询结果返回所有字段,而映射文档限制了查询文档返回的字段

映射运算符

操作符	说明
$	投影数组筛选条件与find命令中的筛选条件相同可以使用"field.$" : true,`(引号是必须的)`.来替代$elemMatch
$elemMatch	遍历数组字段中的每一个元素,找到符合匹配条件的数组字段,并返回数组字段中的满足条件的第一个元素
$slice	限制从阵列映射的元素数。支持跳过和限制切片

语法

db.qvbilam.find(<>,),projection为显示或者不显示的字段,值的格式为:, : .value的值代表显示或者不显示,可以是1, 0也可以是true, false. 也可一

默认情况显示_id,字段
value = 1 或 true 时,字段显示
value = 0 或 false 时,字段不显示
value 可以是映射运算符

映射的字段要么全显示要么全不显示,不能混合使用. _id除外,因为_id为特殊字段

示例

# 不使用映射查询的结果,方便和下面的示例进行对比
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
})

# 返回如下
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

显示字段

# 只显示name,location 字段
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: true })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

不显示字段

# 不显示_id,name字段
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ _id: false, name: false })

# 返回
{ "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

显示混合使用

当混合使用的字段为_id

#  不显示_id,显示name
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ _id: false, name: true })

# 返回
{ "name" : "PiaoYao" }
{ "name" : "ZhaoX" }

当混合使用的字段不为_id

# 不显示num, 显示name
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ num: false, name: true })

# 返回错误
Error: error: {
    "ok" : 0,
    "errmsg" : "Cannot do inclusion on field name in exclusion projection",
    "code" : 31253,
    "codeName" : "Location31253"
}

$

# 查询locaiton大于等于Z,投影条件与查找的筛选条件相同时
db.qvbilam.find({
  location: { $gte: "Z" }
},{ _id: false, name: true, "location.$": true })

# 返回
{ "name" : "XianXian", "location" : "河北" }
{ "name" : "ZhaoX", "location" : [ "ZheJiang" ] }

$elemMatch

# 遍历每个location数组里的元素有其中一条 > HangZhou的值,并返回该数组字段满足条件的第一个值
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $elemMatch: {$gt: "HangZhou"} } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "HeBei" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "ZheJiang" ] }

返回结果说明

第一个返回值数组为[ "HeBei", "ShiJiaZhuang", "ShenZe" ]
第一个返回值按字母排序 HeBei > HangZhou所以显示
第二个返回值数组为[ "ZheJiang", "HangZhou", "XiaoShan" ]
第二个返回值按字母排序 ZheJiang > HangZhou,所以显示

$slice

#----------------------------------------------------

# 返回location数组字段中的第一个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: 1 } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "HeBei" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "ZheJiang" ] }


#----------------------------------------------------

# 返回location数组字段中的最后一个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: -1 } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "XiaoShan" ] }

#----------------------------------------------------

# 返回location数组字段中的第一个元素和第三个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: [1, 3] } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "HangZhou", "XiaoShan" ] }

游标

说明

db.collection.find()返回的是一个游标结果,访问文档需要遍历这个游标值。当遍历完游标后或者没遍历完游标10分钟后会自动关闭游标.

可以使用var Cursor = db.collection.find().noCursorTimeout()防止未遍历完的游标在10分钟后自动关闭.可以使用Cursor.close()主动关闭

游标方法

组合使用游标方法的顺序 sort > skip > limit

方法	示例	说明
count	myCursor.count(bool)	对文档计数,当bool为true时不回考虑limit进行计数.默认为true
close()	myCursor.clos()	关闭游标
forEach()	myCursor.forEach(function)	遍历游标funtion为遍历输出的样式
hasNext()	myCursor.hasNext	是否还有下一个游标
next()	myCursor.next()	下个游标
limit()	myCursor.limit(n)	显示游标数量
skip()	myCursor.skip(n)	跳过游标数量
sort	myCursor.sort({<field1>:<order>,<field2>:<order>,...})	对文档进行排序.order为1正序

示例

声明游标

使用var

# 生命user为查询的结果
var user = db.qvbilam.find({ num: {$gt: 30} })
# 没有自动遍历文档
>

# 调用游标
user
# 返回
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

# 再次调用游标
user
# 返回空
>

不使用var

user = db.qvbilam.find({ num: {$gt: 30} })
# 直接返回结果
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

# 再次调用
user
# 无结果返回
>

$forEach

# 遍历以json格式输出
db.qvbilam.find().forEach(printjson)

# 返回部分结果
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{
    "_id" : ObjectId("602f55994efaa03816f5dbfc"),
    "name" : "qvbilam",
    "num" : 10
}

$skip

# 获取文档数量
db.qvbilam.count()

# 返回文档数量
13

# 获取跳过前10条文档的结果(显示后13 - 10条)
db.qvbilam.find().skip(10)

# 返回
{ "_id" : ObjectId("602f5866c4f596e5b431db1c"), "name" : "XianXian", "num" : 21, "location" : "河北" }
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

$sort

# 对num进行排序
db.qvbilam.find().sort({ num: 1 })

# 返回
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55994efaa03816f5dbfc"), "name" : "qvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfd"), "name" : "GuoOne", "num" : 15 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfe"), "name" : "GuoTwo", "num" : 20 }
{ "_id" : ObjectId("602f561e4efaa03816f5dbff"), "name" : "GuoThree", "num" : 21 }
{ "_id" : ObjectId("602f5866c4f596e5b431db1c"), "name" : "XianXian", "num" : 21, "location" : "河北" }
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f561e4efaa03816f5dc00"), "name" : "GuoFour", "num" : 22 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc01"), "name" : "GuoFive", "num" : 25 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

Last modification：February 20th, 2021 at 04:07 pm

MongoDb——查询文档

二滑大魔王 • 2021 年 02 月 20 日

操作符

比较操作符

当在字符串使用gt/lt这种比较操作符时,会查询出字符串首字母按字典排序之后/之前的内容

操作符	query语法	说明
eq	{ <field> : {$eq: <value>} }	等于
ne	{ <field> : {$ne: <value>} }	不等于
gt	{ <field> : {$gt: <value>} }	大于
gte	{ <field> : {$gte: <value>} }	大于等于
lt	{ <field> : {$lt: <value>} }	小于
lte	{ <field> : {$lte: <value>} }	小于等于
in	{ <field> : {$ne: <value>} }	在区间
nin	{ <field> : {$ne: <value>} }	不在区间

逻辑操作符

操作符	query语法	说明
not	{ <field>: { $not: {expression} } }	匹配条件不成立的文档
and	{ $and: [{<experssion1>,<expression2>,....}] }	匹配条件全部成立的文档
or	{ $or: [<experssion1>,<experssion2>,...] }	匹配条件至少成立一条的文档
nor	{ $nor: [<experssion1>,<experssion2>,...] }	匹配条件全部不成立的文档

字段操作符

操作符	query语法	说明
exists	{ <field>: { $exists: <bool> } }	匹配字段存在的文档
type	{ <field>: {<fieldType>} } or { <field>: [{<fieldType1>,<fieldType2>}] }	匹配字段符合类型的文档

数组操作符

操作符	query语法	说明
all	{ <field>: [<value>,<value>,...] }	匹配数组字段中包含所有值的文档
elemMatch	{ <field>: {<query1>,<query2>,...} }	匹配字段数组里任意一个元素满足其中的条件即可

运算操作符

操作符	query语法	说明-
$regex	{ <fidld>: { $regex: /patten/ : '<options>'} } 或 { <fidld>: {/patten/ '<options>'} }`(与\$in 使用的时候只能用第二种语法)`	匹配字段满足正则表达式的文档

查询方法

语法

查询命令为:db.<collection>.find(<query>,<projection>).<collection>为要查询的集合名称<projection>为查询的映射,相当于sql中需要查询的字段.

<query>为查询条件其语法为{<field> : {$<op>: <value>}}. 其中<field>为要匹配的字段名.$<op>为匹配符.注意在匹配符前面需要加上$.例如,不等于就应该写作$ne.<value>为匹配值.

示例

查询所有文档的全部字段

# 查询所有文档的全部字段
> db.qvbilam_user.find()

# 返回如下
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

查询姓名为gy的文档

# 查询姓名为gy的文档
> db.qvbilam_user.find({ name: "gy" })

# 返回如下
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }

$gte

- 查询数量大于等于15的文档

# 查询数量大于等于15的文档
> db.qvbilam_user.find({ num: {$gte: 14}  })

# 返回结果
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }

$gt

- 查询姓名大于gy的文档

# 查询姓名大于gy的文档
> db.qvbilam_user.find({ name:{$gt: "gy"} })

# 结果返回 s > g的内容
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$in

- 查询姓名为PEPSI或Coca cola

# 查询姓名为PEPSI或Coca cola
> db.qvbilam_user.find({ name: {$in: ["Coca cola", "PEPSI"]} })

# 返回结果如下
{ "_id" : ObjectId("5f39092de9b6f99fc04f2b79"), "name" : "PEPSI", "num" : 20 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }

$not, $in

- 查询姓名为PEPSI或Coca cola不成立的结果

# 查询姓名为PEPSI或Coca cola不成立的结果
> db.qvbilam_user.find({ name: {$not: {$in:  ["Coca cola", "PEPSI"]}} })

# 返回结果如下
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b78"), "name" : "GuoThree", "num" : 14 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7e"), "name" : "save1", "num" : 1 }
{ "_id" : ObjectId("5f3918c1e9b6f99fc04f2b7f"), "name" : "save2", "num" : 2 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$and, $gt,$lte

- 查询数量大于10 并且小于等于13的文档

# 查询数量大于10 并且小于等于13的文档
> db.qvbilam_user.find({
...   $and: [
...     {num: {$gt: 10}},
...     {num: {$lte: 13}}
...   ]
... })

# 返回结果
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0752"), "name" : "Cc", "num" : 13 }
{ "_id" : ObjectId("5f39049673936f515e5c0753"), "name" : "Py", "num" : 13 }
{ "_id" : ObjectId("5f390671e9b6f99fc04f2b77"), "name" : "GuoTwo", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7a"), "name" : "Coca cola", "num" : 13 }
{ "_id" : ObjectId("5f390b1ee9b6f99fc04f2b7b"), "name" : "gy", "num" : 12 }
{ "_id" : ObjectId("5f391930e9b6f99fc04f2b80"), "name" : "save", "num" : 12 }

$and

- 简写

# 字段相同的情况下and的简写
> db.qvbilam_user.find({
...   num: {$gt:10, $lte:13}
... })

# 字段不通情况下and的简写
> db.qvbilam_user.find({
...   name: {$eq: "gy"},
...   num: {$lte: 13}
... })

$exists

- 查询存在num字段的文档

# 查询存在num字段的文档
> db.qvbilam_user.find({ num: {$exists: true} })

$type

- 查询_id字段类型为string的文档

# 查询_id字段类型为string的文档
> db.qvbilam_user.find({ _id: {$type: "string"} })
# 返回结果
{ "_id" : "qvbilam_01", "name" : "errorName", "num" : 13 }

- 查询_id字段类型为string和objectId的文档

# 查询_id字段类型为string和ObjectId的文档
db.qvbilam_user.find({ _id: {$type: ["string","objectId"]} })

$all

- 查询满足所有数组字段的文档

# 创建用户地址数组
> db.qvbilam_user.insert([
...  {
...    name: "MoFan",
...    num: 13,
...    location: ["China","Hebei","ShiJiaZhuang"],
...    mobile: 13211111111
...  },
...  {
...    name: "JunJie",
...    num: 14,
...    location: ["China","ZheJiang","HangZhou"],
...    mobile: 13222222222
...  },
...  {
...    name: "LvKe",
...    num: 15,
...    location: ["China","BeiJing","ChaoYang"],
...    mobile: [13233333333,13244444444,13255555555]
...  }
... ])

# 通过$all查询满足在中国,浙江,杭州的文档
> db.qvbilam_user.find({
...    location: { $all: ["China","ZheJiang","HangZhou"] }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1a"), "name" : "JunJie", "num" : 14, "location" : [ "China", "ZheJiang", "HangZhou" ], "mobile" : 13222222222 }

# 通过$all查询手机号是13233333333,13244444444,13255555555
> db.qvbilam_user.find({
...   mobile: { $all: [[13233333333, 13244444444,13255555555]] }
... })

# 返回
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$elemMatch

- 匹配数组字段至少满足一个值的文档

# 查询手机号在13220000000,13240000000的文档
> db.qvbilam_user.find({
...   mobile: { $elemMatch: { $gt:13211111111, $lte:13240000000} }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$all, $elemMatch

- 满足多个条件的数组

# 查询条件为手机号在13210000000～1322000000之间 同时另一个元素满足 132400000000～13250000000之间的文档
> db.qvbilam_user.find({
...   mobile:{ $all: [
...       {$elemMatch: {$gt: 13230000000,$lt:13240000000}},
...       {$elemMatch: {$gt: 13240000000,$lt:13260000000}}
...       ] }
... })

# 返回如下
{ "_id" : ObjectId("5f3d31f16dbe86c585d88d1b"), "name" : "LvKe", "num" : 15, "location" : [ "China", "BeiJing", "ChaoYang" ], "mobile" : [ 13233333333, 13244444444, 13255555555 ] }

$regex

第一种写法

# 查询名称包含guo且不区分大小写的文档
db.qvbilam.find({ name: {$regex: /guo/, $options: "i"} })

# 返回
{ "_id" : ObjectId("602f55e24efaa03816f5dbfd"), "name" : "GuoOne", "num" : 15 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfe"), "name" : "GuoTwo", "num" : 20 }
{ "_id" : ObjectId("602f561e4efaa03816f5dbff"), "name" : "GuoThree", "num" : 21 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc00"), "name" : "GuoFour", "num" : 22 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc01"), "name" : "GuoFive", "num" : 25 }

第二种写法

# 查询名称以 a 或 q开偷的文档
db.qvbilam.find({ name: { $in: [/^a/,/^q/] } })

# 返回如下
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55994efaa03816f5dbfc"), "name" : "qvbilam", "num" : 10 }

映射

默认查询结果返回所有字段,而映射文档限制了查询文档返回的字段

映射运算符

操作符	说明
$	投影数组筛选条件与find命令中的筛选条件相同可以使用"field.$" : true,`(引号是必须的)`.来替代$elemMatch
$elemMatch	遍历数组字段中的每一个元素,找到符合匹配条件的数组字段,并返回数组字段中的满足条件的第一个元素
$slice	限制从阵列映射的元素数。支持跳过和限制切片

语法

db.qvbilam.find(<>,),projection为显示或者不显示的字段,值的格式为:, : .value的值代表显示或者不显示,可以是1, 0也可以是true, false. 也可一

默认情况显示_id,字段
value = 1 或 true 时,字段显示
value = 0 或 false 时,字段不显示
value 可以是映射运算符

映射的字段要么全显示要么全不显示,不能混合使用. _id除外,因为_id为特殊字段

示例

# 不使用映射查询的结果,方便和下面的示例进行对比
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
})

# 返回如下
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

显示字段

# 只显示name,location 字段
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: true })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

不显示字段

# 不显示_id,name字段
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ _id: false, name: false })

# 返回
{ "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

显示混合使用

当混合使用的字段为_id

#  不显示_id,显示name
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ _id: false, name: true })

# 返回
{ "name" : "PiaoYao" }
{ "name" : "ZhaoX" }

当混合使用的字段不为_id

# 不显示num, 显示name
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ num: false, name: true })

# 返回错误
Error: error: {
    "ok" : 0,
    "errmsg" : "Cannot do inclusion on field name in exclusion projection",
    "code" : 31253,
    "codeName" : "Location31253"
}

$

# 查询locaiton大于等于Z,投影条件与查找的筛选条件相同时
db.qvbilam.find({
  location: { $gte: "Z" }
},{ _id: false, name: true, "location.$": true })

# 返回
{ "name" : "XianXian", "location" : "河北" }
{ "name" : "ZhaoX", "location" : [ "ZheJiang" ] }

$elemMatch

# 遍历每个location数组里的元素有其中一条 > HangZhou的值,并返回该数组字段满足条件的第一个值
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $elemMatch: {$gt: "HangZhou"} } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "HeBei" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "ZheJiang" ] }

返回结果说明

第一个返回值数组为[ "HeBei", "ShiJiaZhuang", "ShenZe" ]
第一个返回值按字母排序 HeBei > HangZhou所以显示
第二个返回值数组为[ "ZheJiang", "HangZhou", "XiaoShan" ]
第二个返回值按字母排序 ZheJiang > HangZhou,所以显示

$slice

#----------------------------------------------------

# 返回location数组字段中的第一个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: 1 } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "HeBei" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "ZheJiang" ] }


#----------------------------------------------------

# 返回location数组字段中的最后一个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: -1 } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "XiaoShan" ] }

#----------------------------------------------------

# 返回location数组字段中的第一个元素和第三个元素
db.qvbilam.find({
  $or: [ {name: "PiaoYao"}, {name: "ZhaoX"}]
},{ name: true, location: { $slice: [1, 3] } })

# 返回
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "location" : [ "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "location" : [ "HangZhou", "XiaoShan" ] }

游标

说明

db.collection.find()返回的是一个游标结果,访问文档需要遍历这个游标值。当遍历完游标后或者没遍历完游标10分钟后会自动关闭游标.

可以使用var Cursor = db.collection.find().noCursorTimeout()防止未遍历完的游标在10分钟后自动关闭.可以使用Cursor.close()主动关闭

游标方法

组合使用游标方法的顺序 sort > skip > limit

方法	示例	说明
count	myCursor.count(bool)	对文档计数,当bool为true时不回考虑limit进行计数.默认为true
close()	myCursor.clos()	关闭游标
forEach()	myCursor.forEach(function)	遍历游标funtion为遍历输出的样式
hasNext()	myCursor.hasNext	是否还有下一个游标
next()	myCursor.next()	下个游标
limit()	myCursor.limit(n)	显示游标数量
skip()	myCursor.skip(n)	跳过游标数量
sort	myCursor.sort({<field1>:<order>,<field2>:<order>,...})	对文档进行排序.order为1正序

示例

声明游标

使用var

# 生命user为查询的结果
var user = db.qvbilam.find({ num: {$gt: 30} })
# 没有自动遍历文档
>

# 调用游标
user
# 返回
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

# 再次调用游标
user
# 返回空
>

不使用var

user = db.qvbilam.find({ num: {$gt: 30} })
# 直接返回结果
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

# 再次调用
user
# 无结果返回
>

$forEach

# 遍历以json格式输出
db.qvbilam.find().forEach(printjson)

# 返回部分结果
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{
    "_id" : ObjectId("602f55994efaa03816f5dbfc"),
    "name" : "qvbilam",
    "num" : 10
}

$skip

# 获取文档数量
db.qvbilam.count()

# 返回文档数量
13

# 获取跳过前10条文档的结果(显示后13 - 10条)
db.qvbilam.find().skip(10)

# 返回
{ "_id" : ObjectId("602f5866c4f596e5b431db1c"), "name" : "XianXian", "num" : 21, "location" : "河北" }
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

$sort

# 对num进行排序
db.qvbilam.find().sort({ num: 1 })

# 返回
{ "_id" : "qvbilam_01", "name" : "angelQvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55994efaa03816f5dbfc"), "name" : "qvbilam", "num" : 10 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfd"), "name" : "GuoOne", "num" : 15 }
{ "_id" : ObjectId("602f55e24efaa03816f5dbfe"), "name" : "GuoTwo", "num" : 20 }
{ "_id" : ObjectId("602f561e4efaa03816f5dbff"), "name" : "GuoThree", "num" : 21 }
{ "_id" : ObjectId("602f5866c4f596e5b431db1c"), "name" : "XianXian", "num" : 21, "location" : "河北" }
{ "_id" : ObjectId("602f7e8dc4f596e5b431db1d"), "name" : "PiaoYao", "num" : 21, "location" : [ "HeBei", "ShiJiaZhuang", "ShenZe" ] }
{ "_id" : ObjectId("602f561e4efaa03816f5dc00"), "name" : "GuoFour", "num" : 22 }
{ "_id" : ObjectId("602f561e4efaa03816f5dc01"), "name" : "GuoFive", "num" : 25 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc02"), "name" : "HelloOne", "num" : 31 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc03"), "name" : "HelloTwo", "num" : 32 }
{ "_id" : ObjectId("602f563e4efaa03816f5dc04"), "name" : "HelloThree", "num" : 35 }
{ "_id" : ObjectId("602f7eccc4f596e5b431db1e"), "name" : "ZhaoX", "num" : 50, "location" : [ "ZheJiang", "HangZhou", "XiaoShan" ] }

操作符

比较操作符

逻辑操作符

字段操作符

数组操作符

运算操作符

查询方法

语法

示例

$gte

$gt

$in

$not, $in

$and, $gt,$lte

$and

$exists

$type

$all

$elemMatch

$all, $elemMatch

$regex

映射

映射运算符

语法

示例

显示字段

不显示字段

显示混合使用

$

$elemMatch

$slice

游标

说明

游标方法

示例

声明游标

$forEach

$skip

$sort