数据库mongodb，MongoDB语法与现有关系型数据库SQL语法比较

2023-09-25 阅读 21 评论 0

摘要：MongoDB语法与现有关系型数据库SQL语法比较 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.fi

MongoDB语法与现有关系型数据库SQL语法比较

MongoDB语法	MySql语法
db.test.find({‘name’:‘foobar’})	select * from test where name=‘foobar’
db.test.find()	select *from test
db.test.find({‘ID’:10}).count()	select count(*) from test where ID=10
db.test.find().skip(10).limit(20)	select * from test limit 10,20
db.test.find({‘ID’:{$in:[25,35,45]}})	select * from test where ID in (25,35,45)
db.test.find().sort({‘ID’:-1})	select * from test order by IDdesc
db.test.distinct(‘name’,{‘ID’:{$lt:20}})	select distinct(name) from testwhere ID<20
db.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 whereID<20
db.test.insert({‘name’:‘foobar’,‘age’:25})	insertinto test (‘name’,‘age’) values(‘foobar’,25)
db.test.remove({})	delete from test
db.test.remove({‘age’:20})	delete test where age=20
db.test.remove({‘age’:{$lt:20}})	delete test where age<20
db.test.remove({‘age’:{$lte:20}})	delete test where age<=20
db.test.remove({‘age’:{$gt:20}})	delete test where age>20
db.test.remove({‘age’:{$gte:20}})	delete test where age>=20
db.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’

模糊查询：$regex

db.test.find({“name”:{$regex:“aaa”}})

分组个数过滤

数据库mongodb？db.getCollection(‘id_mapper’).aggregate([{ $KaTeX parse error: Expected '}', got 'EOF' at end of input: group:{ _id :"$ contract_id",count:{ $KaTeX parse error: Expected 'EOF', got '}' at position 6: sum:1}̲}},{$ match:{count:{$gt:1}}}])

判断是否为空

db.getCollection(‘id_mapper’).find({“sinocardid”:{$in:[null]}})

原文链接：https://hbdhgg.com/2/96556.html

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