MongoDB语法                                  MySql语法db.test.find({
    'name':'foobar'})<==> select * from test where name='foobar'db.test.find()                            <==> select *from testdb.test.find({
    'ID':10}).count()<==> select count(*) from test where ID=10db.test.find().skip(10).limit(20)<==> select * from test limit 10,20db.test.find({
    'ID':{$in:[25,35,45]}})<==> select * from test where ID in (25,35,45)db.test.find().sort({
    'ID':-1})  <==> select * from test order by IDdescdb.test.distinct('name',{
   'ID':{$lt:20}})  <==> select distinct(name) from testwhere ID<20db.test.group({
   key:{
   'name':true},cond:{
   'name':'foo'},reduce:function(obj,prev){prev.msum+=obj.marks;},initial:{msum:0}})  <==> select name,sum(marks) from testgroup by name db.test.find('this.ID<20',{name:1})  <==> select name from test where ID < 20db.test.insert({
   'name':'foobar','age':25})<==>insert into test ('name','age') values('foobar',25)db.test.remove({})                        <==> delete * from testdb.test.remove({
    'age':20})            　　<==> delete test where age=20db.test.remove({
    'age':{$lt:20}})   　　　　<==> delete test where age<20db.test.remove({
    'age':{$lte:20}})  　　　　<==> delete test where age<=20db.test.remove({
    'age':{$gt:20}})  　　　　 <==> delete test where age>20db.test.remove({
    'age':{$gte:20}})　　　　　<==> delete test where age>=20db.test.remove({
    'age':{$ne:20}})  　　　　 <==> delete test where age!=20 db.test.update({
   'name':'foobar'},{$set:{
   'age':36}})<==> update test set age=36 where name='foobar'db.test.update({
   'name':'foobar'},{$inc:{
   'age':3}})<==> update test set age=age+3 where name = ‘foobar’