MongoDB's Find () operation

Create a database

Performing an operation into MongoDB using parameter mode can also be verified using Db.auth ().

[Email protected]:/usr/local/apache243/htdocs#  /usr/local/mongodb/mongo  -uroot-pxxxxx localhost : 27017/admin

The following is the first time a new database is created

 Use demoswitched to db DEMO> Db.user.insert ({name: "Zhaoxingzhuang", Age:18,sex: "Man", Location:{province: " Shandong ", City:" Jinan ", Road:" shandaroad-47 "" ninserted ": 1 })> Db.user.find ()  // All Queries {"_id": ObjectId ("54feea0a26be41dca9db0d23"), "name": "Zhaoxingzhuang", "age": +, "sex": "Man", "location": {"Prov Ince ":" Shandong "," City ":" Jinan "," Road ":" Shandaroad-47 " }}

Continue with the insert operation

1, simple query find ({field: "Value"},{field:0 or 1}), before the condition of the query indicates that the query field 0 means that the field is not displayed 1 indicates that only this field is displayed

> Db.user.insert ({name: "Wangping", Age:26,sex: "Woman", Location:{city: "Beijing", Road: "Zhongguonongyedaxue"}}) Writeresult ({"Ninserted": 1 })> Db.user.find () {"_id": ObjectId ("54feea0a26be41dca9db0d23"), "name": "Zhaoxingzhuang", "age": +, "sex": "Man", "location": {"Provin Ce ":" Shandong "," City ":" Jinan "," Road ":" Shandaroad-47 " } }{ "_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "B Eijing "," Road ":" Zhongguonongyedaxue " } }> Db.user.find ({name: "Wangping"})//query Name= "wangping"{"_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "Beijing", "Road": "Zhongguonongyedaxue" } }//The field selects Select Age from XXX in a similar SQL statement;> Db.user.find ({name: "wangping"},{age:0})//indicates that the age field is not displayed{"_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "Sex": "Woman", "location": {"City": "Beijing", " Road ":" Zhongguonongyedaxue " } }> Db.user.find ({name: "wangping"},{age:1})//indicates that only the age field is taken{"_id": ObjectId ("54feead226be41dca9db0d24"), "age": 26 }>

2, Condition Inquiry > $gt, < $lt, <= $lte, >= $gte.

> Db.user.find ({age:{$gt: +})   // query {"_id" for age greater than 20 : ObjectId (" 54feead226be41dca9db0d24 ")," name ":" Wangping "," age ": +," sex ":" Woman "," location ": {" City ":" Beijing "," Road ": "Zhongguonongyedaxue" }}

3. $all operation is only valid for the array (similar to $in), which represents the $all to query: [1,2,5,6] 1256 must be all in the arrays to be queried, and $in means that the query criteria are met whenever one is available.

> Db.user.insert ({name: "Gaofei", Age:24,grade:[1,2,5,6],location:{province: "Shandong", City: "Jiyang", Road: " Zuozhuangzhen "" ninserted ": 1 })> Db.user.find (grade:{$all: [1,2,5,6]}) 2015-03-10t21:19:20.164+0800 syntaxerror:unexpected token:> db.user.find ({grade:{$all: [1,2,5,6]}})    //$all  query condition {"_id": ObjectId ("54feef3626be41dca9db0d25"), "name": "Gaofei", "age": 24, " Grade ": [1, 2, 5, 6]," location ": {" province ":" Shandong "," City ":" Jiyang "," Road ":" Zuozhuangzhen " }}

$all $in just used on the array

> Db.user.find ({name:{$all: [1,2,5,6]}})   // field is not an array  of cases > Db.user.find ({ name:{$in: [1]})> Db.user.find ({grade:{$in: [1]})       //$in use Query {"_id": ObjectId ("54feef3626be41dca9db0d25"), "name": "Gaofei", "Age": 5, "Grade": [1, 2,, 6], "Location" : {"Province": "Shandong", "City": "Jiyang", "Road": "Zuozhuangzhen" }}

4, skip () limit () count () sort () use

Where skip and limit are used similar to the SELECT * from user limit 0, 10 in SQL statements;

> Db.user.find ()//list them in the order of addition{"_id": ObjectId ("54feea0a26be41dca9db0d23"), "name": "Zhaoxingzhuang", "age": +, "sex": "Man", "location": {"Prov Ince ":" Shandong "," City ":" Jinan "," Road ":" Shandaroad-47 " } }{ "_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "B Eijing "," Road ":" Zhongguonongyedaxue " } }{ "_id": ObjectId ("54feef3626be41dca9db0d25"), "name": "Gaofei", "Age": 5, "Grade": [1, 2,, 6], "location": {"pro Vince ":" Shandong "," City ":" Jiyang "," Road ":" Zuozhuangzhen " } }//Limit Zero-based query two> Db.user.find (). Limit (2){ "_id": ObjectId ("54feea0a26be41dca9db0d23"), "name": "Zhaoxingzhuang", "age": +, "sex": "Man", "location": {"Provin Ce ":" Shandong "," City ":" Jinan "," Road ":" Shandaroad-47 " } }{ "_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "B Eijing "," Road ":" Zhongguonongyedaxue " } }> Db.user.skip (1).limit ()2015-03-10t21:26:17.430+0800 typeerror:property ' Skip ' ofObjectDemo.user is not afunction> Db.user.find (). Skip (1). Limit ()//start with the first one .{"_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "Beijing", "Road": "Zhongguonongyedaxue" } }{ "_id": ObjectId ("54feef3626be41dca9db0d25"), "name": "Gaofei", "Age": 5, "Grade": [1, 2,, 6], "location": {"pro Vince ":" Shandong "," City ":" Jiyang "," Road ":" Zuozhuangzhen " } }> Db.user.Count()//Total Statistical Data3> Db.user.find ().Sort(age:1)//you have to put the sorted contents in the {}2015-03-10t21:27:49.863+0800 syntaxerror:unexpected token:> db.user.find ().Sort({age:1}){ "_id": ObjectId ("54feea0a26be41dca9db0d23"), "name": "Zhaoxingzhuang", "age": +, "sex": "Man", "location": {"Provin Ce ":" Shandong "," City ":" Jinan "," Road ":" Shandaroad-47 " } }{ "_id": ObjectId ("54feef3626be41dca9db0d25"), "name": "Gaofei", "Age": 5, "Grade": [1, 2,, 6], "location": {"pro Vince ":" Shandong "," City ":" Jiyang "," Road ":" Zuozhuangzhen " } }{ "_id": ObjectId ("54feead226be41dca9db0d24"), "name": "Wangping", "age": +, "sex": "Woman", "location": {"City": "B Eijing "," Road ":" Zhongguonongyedaxue " } }>

MongoDB find () operation