MySQL语法

MongoDB语法

select * from t1;

db.t1.find({},{_id:0})

select id,name from t1;

db.t1.find({},{_id:0,id:1,name:1})

select id,name from t1 limit 1;

db.t2.findOne({},{_id:0,id:1,name:1})

select id,name from t1 limit 10;

db.t1.find({},{_id:0,id:1,name:1}).limit(10)

select id,name from t1 limit 10,4;

db.t1.find({},{_id:0,id:1,name:1}).skip(10).limit(4)

select id,name from t1 order by id

desc limit 10;

db.t1.find({},{_id:0,id:1,name:1}).limit(10).sort({id:-1})

select id,name from t1 where id=2;

db.t1.find({id:2},{_id:0,cid:1,name:1})

select id,name from t1 where i

d>=2;

db.t1.find({id:{$gte:2}},{_id:0,cid:1,name:1})

select id,name from t1 where i

d>=2 AND id <=10;

db.t1.find({id:{$gte:2,$lte:10}},{_id:0,cid:1,name:1})

select id,name from t1 where id in (1,3,5);

db.t1.find({id:{$in:[1,3,5]}},{_id:0,cid:1,name:1})

select id,name from t1 where i

d=1 AND name =’a’;

db.t1.find({$and:[{id:1},{name:"a"}]},{_id:0,cid:1,name:1})

select id,name from t1 where i

d=1 OR name =’a’;

db.t1.find({$or:[{id:1},{name:"a"}]},{_id:0,cid:1,name:1})

select count(*) from t1;

db.t1.find().count()

select distinct(name) from t1;

db.t1.distinct('name').count()

select count(*) from t1;

db.t1.aggregate({$group:{_id:null,count:{$sum:1}}})

select sum(cid) from t1;

db.t1.aggregate({$group:{_id:null,sum:{$sum:'$cid'}}})

select sum(cid) from t1 group by

name;

db.t1.aggregate({$group:{_id:'$name',sum:{$sum:'$cid'}}})

select count(*) from t1 where

name=’ABC’ group by class_id ;

db.t2.aggregate({$match:{name:"ABC"}},{$group:{_id:’class_id’,count:{$sum:1}}})

select count(*) from t1 group by

name having count(*) >2;

db.t1.aggregate({$group:{_id:'name',count:{$sum:1}}},{$match:{count:{$gt:2}}})

select id,name,count(*) from t1 

group by id,name having

count(*) >=1;

db.t1.aggregate({$project:{id:1,"name":1}},{$match:{name:"bb"}},{$group:{"_id":{id:"$id",name:"$name"},count:{$sum:1}}}, {$match:{count:{$gte:1}}})



insert into t1(cid,name)

values(5,’B’),(6,’C’);

db.t1.insertMany([{cid:5,name:"B"},{cid:6,name:"C"}])

replace into t1(cid,name)

values(7,’D’);

db.t1.update({},{cid:7,name:"D"},{upsert:1})

update t1 set name=’A’ where

name=’a’;

db.t1.update({name:"a"},{$set:{name:"A"}},{multi:1})

update t1 set cid=cid+10 where

cid=’6’;

db.t1.update({cid:6},{$inc:{cid:10}})

delete from t1 where name = ‘D’;

db.t1.remove({name:"D"})

db.t1.deleteMany({name:"D"})


alter table t1 drop column name;

db.t1.update({},{$unset:{name:1}},{multi:1})