MongoDB command and SQL syntax comparison

MongoDB vs. mysql command comparison

The traditional relational database is usually composed of three hierarchical concepts of database, table, record, and MongoDB is made up of database, collection (collection), Three levels of document objects. MongoDB is for tables in relational databases, but there is no concept of columns, rows, and relationships in the collection, which embodies the nature of pattern freedom.

Mysql	Mongodb	Description
Mysqld	Mongod	Server daemon
Mysql	Mongo	Client Tools
Mysqldump	Mongodump	Logical Backup tool
Mysql	Mongorestore	Logical Recovery Tool
	Db.repairdatabase ()	Repairing the database
Mysqldump	Mongoexport	Data Export Tool
Source	Mongoimport	Data Import Tool
Grant * privileges on *.	Db.adduser () Db.auth ()	New User and Permissions
Show databases	Show DBS	Show Library List
Show tables	Show Collections	Show Table List
Show slave status	Rs.status	Querying master-Slave status
Create table Users (a int, b int)	Db.createcollection ("Mycoll", {capped:true, size:100000}) Another: The table can be created implicitly.	Create a table
Create INDEX idxname on users (name)	Db.users.ensureIndex ({name:1})	Create an index
Create INDEX idxname on users (Name,ts DESC)	Db.users.ensureIndex ({name:1,ts:-1})	Create an index
Insert into users values (1, 1)	Db.users.insert ({a:1, b:1})	Inserting records
Select A, B from users	Db.users.find ({},{a:1, b:1})	Query table
Select * from users	Db.users.find ()	Query table
Select * from users where age=33	Db.users.find ({age:33})	Conditional query
Select A, b from users where age=33	Db.users.find ({age:33},{a:1, b:1})	Conditional query
SELECT * from Users where age<33	Db.users.find ({' age ': {$lt: 33}})	Conditional query
SELECT * from users where age>33 and age<=40	Db.users.find ({' age ': {$gt:, $lte: 40}})	Conditional query
SELECT * from users where a=1 and b= ' Q '	Db.users.find ({a:1,b: ' Q '})	Conditional query
SELECT * from users where a=1 or b=2	Db.users.find ({$or: [{a:1}, {b:2}]})	Conditional query
SELECT * from users limit 1	Db.users.findOne ()	Conditional query
SELECT * from the users where name like "%joe%"	Db.users.find ({name:/joe/})	Fuzzy query
SELECT * from the users where name like "joe%"	Db.users.find ({name:/^joe/})	Fuzzy query
Select COUNT (1) from users	Db.users.count ()	Get table Record Count
Select COUNT (1) from users where age>30	Db.users.find ({age: {' $GT ': $}}). Count ()	Get table Record Count
Select DISTINCT last_name from Users	Db.users.distinct (' last_name ')	Remove duplicate values
SELECT * from the users ORDER by name	Db.users.find (). Sort ({name:-1})	Sort
SELECT * from Users ORDER by name DESC	Db.users.find (). Sort ({name:-1})	Sort
EXPLAIN SELECT * from Users where z=3	Db.users.find ({Z:3}). Explain ()	Get Storage Path
Update users set a=1 where b= ' Q '	Db.users.update ({b: ' Q '}, {$set: {a:1}}, False, True)	Update record
Update users set a=a+2 where b= ' Q '	Db.users.update ({b: ' Q '}, {$inc: {a:2}}, False, True)	Update record
Delete from users where z= "abc"	Db.users.remove ({z: ' abc '})	Deleting records
	Db. Users.remove ()	Delete all the records
Drop database IF EXISTS test;	Use test Db.dropdatabase ()	Deleting a database
drop table IF EXISTS test;	Db.mytable.drop ()	Delete Table/collection
	Db.adduser (' Test ', ' test ')	Add user Readonly-->false
	Db.adduser (' Test ', ' test ', true)	Add user Readonly-->true
	Db.adduser ("Test", "test222")	Change Password
	Db.system.users.remove ({User: "Test"}) or Db.removeuser (' test ')	Delete User

MongoDB syntax

MongoDB benefits Quite a lot, such as multi-column index, query can use some statistical functions, support multi-conditional query, but the current multi-table query is not supported, you can find a way to solve the problem of multi-table query through data redundancy.

MongoDB is very rich in data manipulation, here are some examples, the content is mostly from official documents, in addition to some of their own understanding.

Query Colls all data

Db.colls.find ()//select * from Colls

Querying by specifying criteria

Db.colls.find ({' last_name ': ' Smith '}),//select * from Colls where last_name= ' Smith '

Specify a multi-criteria query

Db.colls.find ({x:3, y: "foo"}),//select * from Colls where x=3 and y= ' foo '

Specify criteria range Query

Db.colls.find ({j: {$ne: 3}, K: {$gt: ten}});//select * from Colls where j!=3 and k>10

Query does not include a content

Db.colls.find ({}, {a:0});//query all data except for a of 0

Support <, <=, >= query, with symbolic substitution for $lt, $lte, $GT, $gte

Db.colls.find ({"field": {$gt: Value}});

Db.colls.find ({"field": {$lt: Value}});

Db.colls.find ({"field": {$gte: Value}});

Db.colls.find ({"field": {$lte: Value}});

You can also make a range query for a field

Db.colls.find ({"field": {$gt: value1, $lt: value2}});

Not equal to query character $ne

Db.colls.find ({x: {$ne: 3}});

In query with character $in

Db.colls.find ({"field": {$in: Array}});

Db.colls.find ({j:{$in: [2,4,6]}});

Not in query with character $nin

Db.colls.find ({j:{$nin: [2,4,6]}});

Character $mod for modulo query

Db.colls.find ({A: {$mod: [ten, 1]}})//where a% 10 = = 1

$all Query

Db.colls.find ({A: {$all: [2, 3]}});//Specifies that a satisfies any value in the array

$size Query

Db.colls.find ({A: {$size: 1});//The number of objects queried, this query queries the number of child objects of a 1 record

$exists Query

Db.colls.find ({A: {$exists: true}}); There is data for the A object

Db.colls.find ({A: {$exists: false}}); There is no data for the A object

$type Query the type value of the $type value to bsonhttp://bsonspec.org/data

Db.colls.find ({A: {$type: 2}}); Match A to string type data

Db.colls.find ({A: {$type: 16}}); Match A to int type data

Using regular expression matching

Db.colls.find ({name:/acme.*corp/i});//similar to SQL

Inline Object Query

Db.colls.find ({"Author.name": "Joe"});

1.3.3 versions and later versions include $not queries

Db.colls.find ({name: {$not:/acme.*corp/i}});

Db.colls.find ({A: {$not: {$mod: [10, 1]}}});

Sort () sorting

Db.colls.find (). Sort ({ts:-1});//1 to ascending 2 to descending

Limit () returns the number of restricted query data

Db.colls.find (). Limit (10)

Skip () skips some data

Db.colls.find (). Skip (10)

Snapshot () snapshot guarantees no duplicate data return or object loss

Count () counts the number of query objects

Db.students.find ({' address.state ': ' CA '}). Count ();//High efficiency

Db.students.find ({' address.state ': ' CA '}). ToArray (). length;//is inefficient

Group () resembles the group by function in SQL by grouping query results

Distinct () returns non-repeating values

MongoDB command and SQL syntax comparison