MongoDB 语法

上行：SQL 操作语句 
下行：Mongo 操作语句 
CREATE TABLE USERS (a Number, b Number) 
db.createCollection("mycoll") 

INSERT INTO USERS VALUES(1,1) 
db.users.insert({a:1,b:1}) 

SELECT a,b FROM users 
db.users.find({}, {a:1,b:1}) 

SELECT * FROM users 
db.users.find() 

SELECT * FROM users WHERE age=33 
db.users.find({age:33}) 

SELECT a,b FROM users WHERE age=33 
db.users.find({age:33}, {a:1,b:1}) 

SELECT * FROM users WHERE age=33 ORDER BY name 
db.users.find({age:33}).sort({name:1}) 

SELECT * FROM users WHERE age>33 
db.users.find({'age':{$gt:33}})}) 

SELECT * FROM users WHERE age<33 
db.users.find({'age':{$lt:33}})}) 

SELECT * FROM users WHERE name LIKE "%Joe%" 
db.users.find({name:/Joe/}) 

SELECT * FROM users WHERE name LIKE "Joe%" 
db.users.find({name:/^Joe/}) 

SELECT * FROM users WHERE age>33 AND age<=40 
db.users.find({'age':{$gt:33,$lte:40}})}) 

SELECT * FROM users ORDER BY name DESC 
db.users.find().sort({name:-1}) 

SELECT * FROM users WHERE a=1 and b='q' 
db.users.find({a:1,b:'q'}) 

SELECT * FROM users LIMIT 10 SKIP 20 
db.users.find().limit(10).skip(20) 

SELECT * FROM users WHERE a=1 or b=2 
db.users.find( { $or : [ { a : 1 } , { b : 2 } ] } ) 

SELECT * FROM users LIMIT 1 
db.users.findOne() 

SELECT DISTINCT last_name FROM users 
db.users.distinct('last_name') 

SELECT COUNT(*y) FROM users 
db.users.count() 

SELECT COUNT(*y) FROM users where AGE > 30 
db.users.find({age: {'$gt': 30}}).count() 

SELECT COUNT(AGE) from users 
db.users.find({age: {'$exists': true}}).count() 

CREATE INDEX myindexname ON users(name) 
db.users.ensureIndex({name:1}) 

CREATE INDEX myindexname ON users(name,ts DESC) 
db.users.ensureIndex({name:1,ts:-1}) 

EXPLAIN SELECT * FROM users WHERE z=3 
db.users.find({z:3}).explain() 

UPDATE users SET a=1 WHERE b='q' 
db.users.update({b:'q'}, {$set:{a:1}}, false, true) 

UPDATE users SET a=a+2 WHERE b='q' 
db.users.update({b:'q'}, {$inc:{a:2}}, false, true) 

DELETE FROM users WHERE z="abc" 
db.users.remove({z:'abc'});