MongoDB入门实操《中篇》续

db.test.find()  ==> select * from test
db.test.findOne()  ==> select *from test limit 1
db.test.find().pretty()  ==>select * from test \G
db.test.find().limit(2)  ==> select * from test limit 2
db.test.find().count()  ==>select count(*) from test
db.test.find().sort({age: 1})  ==>select * from test order by age
db.test.find().sort({age: -1})  ==>select * from test order by age desc
db.test.find({"age" : 1})  ==>select * from test where age = 1
db.test.find({"age":{$gt:29}}).skip(1).limit(3)  ==> select * from test where age>29 limit 1,3;
db.test.find({"name" : "joe", "age" : 1})  ==>select * from test where "name" = "joe" and age = 1
db.test.find({}, {"name" : 1, "age" : 1})  ==>select name, age from test
db.test.find({}, {"name" : 1, "_id" : 0})  ==>select name from test # 这里相当于是不让_id显示出来
db.test.find({"age" : {"$gte" : 18, "$lte" : 30}})  ==>select * from test where age >=18 and age <= 30 // $lt(<) $lte(<=) $gt(>) $gte(>=)
db.test.find({"name" : {"$ne" : "joe"}})  ==>select * from test where name <> "joe"
db.test.find({"age" : {"$in" : [25, 42, 30]}})  ==> select * from test where age in (25, 42, 30)
db.test.find({"age" : {"$nin" : [25, 42, 30]}})  ==>select * from test where age not in (25, 42, 30)
db.test.find({"$or" : [{"age" : 25}, {"job" : "tester"}]})  ==>select * form test where age= 25 or job= "tester"
db.test.find({"$not": {"age" : 27}})  ==>select * from test where not (age = 27)
db.test.find({"name" : {"$in" : [null], "$exists" : true}})  ==> select * from test where name is null 
db.test.find({"name" : /joy?/i})  ==>select * from test where name like "%joy%”