mongodb 与mysql 语法对比

╰半橙微兮° 2022-07-16 01:58 120阅读 0赞

我们总是在对比中看到自己的优点和缺点，对于mongodb来说也是一样，对比学习让我们尽快的掌握关于mongodb的基础知识。

mongodb与mysql命令对比

关系型数据库一般是由数据库（database）、表（table）、记录（record）三个层次概念组成。而非关系型数据库mongodb是由数据库（database）、集合（collection）、文档对象（document）三个层次组成。mongodb对于关系型数据库里的表，没有行和列的关系概念，这体现了模式的自由特点。

语法命令如下列表格所示

<table style="border-width:0px; padding:0px; margin:0px; list-style:none; color:rgb(51,51,51); font-family:宋体; font-size:14px; background-color:rgb(249,249,249)"> 
 <tbody> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> MySQL </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> MongoDB </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 说明 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mysqld </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongod </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 服务器守护进程 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mysql </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongo </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 客户端工具 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mysqldump </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongodump </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 逻辑备份工具 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mysql </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongorestore </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 逻辑恢复工具 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.repairDatabase() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 修复数据库 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mysqldump </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongoexport </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 数据导出工具 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> source </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> mongoimport </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 数据导入工具 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> grant * privileges on *.* to … </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Db.addUser() Db.auth() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 新建用户并权限 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> show databases </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> show dbs </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 显示库列表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Show tables </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Show collections </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 显示表列表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Show slave status </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Rs.status </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查询主从状态 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Create table users(a int, b int) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.createCollection("mycoll", {capped:true, size:100000}) 另：可隐式创建表。 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 创建表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Create INDEX idxname ON users(name) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.ensureIndex({name:1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 创建索引 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Create INDEX idxname ON users(name,ts DESC) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.ensureIndex({name:1,ts:-1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 创建索引 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Insert into users values(1, 1) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.insert({a:1, b:1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 插入记录 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Select a, b from users </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({},{a:1, b:1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查询表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Select * from users </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查询表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Select * from users where age=33 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({age:33}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Select a, b from users where age=33 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({age:33},{a:1, b:1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where age&lt;33 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({'age':{$lt:33}}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where age&gt;33 and age&lt;=40 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({'age':{$gt:33,$lte:40}}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where a=1 and b='q' </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({a:1,b:'q'}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where a=1 or b=2 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find( { $or : [ { a : 1 } , { b : 2 } ] } ) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users limit 1 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.findOne() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 条件查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where name like "%Joe%" </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({name:/Joe/}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 模糊查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users where name like "Joe%" </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({name:/^Joe/}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 模糊查询 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select count(1) from users </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> Db.users.count() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 获取表记录数 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select count(1) from users where age&gt;30 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({age: {'$gt': 30}}).count() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 获取表记录数 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select DISTINCT last_name from users </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.distinct('last_name') </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 去掉重复值 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users ORDER BY name </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find().sort({name:-1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 排序 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> select * from users ORDER BY name DESC </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find().sort({name:-1}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 排序 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> EXPLAIN select * from users where z=3 </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.find({z:3}).explain() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 获取存储路径 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> update users set a=1 where b='q' </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.update({b:'q'}, {$set:{a:1}}, false, true) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 更新记录 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> update users set a=a+2 where b='q' </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.update({b:'q'}, {$inc:{a:2}}, false, true) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 更新记录 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> delete from users where z="abc" </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.remove({z:'abc'}) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 删除记录 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db. users.remove() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 删除所有的记录 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> drop database IF EXISTS test; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> use test db.dropDatabase() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 删除数据库 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> drop table IF EXISTS test; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.mytable.drop() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 删除表/collection </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.addUser(‘test’, ’test’) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 添加用户 readOnly--&gt;false </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.addUser(‘test’, ’test’, true) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 添加用户 readOnly--&gt;true </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.addUser("test","test222") </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 更改密码 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.system.users.remove({user:"test"}) 或者db.removeUser('test') </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 删除用户 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> use admin </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 超级用户 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.auth(‘test’, ‘test’) </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 用户授权 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.system.users.find() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看用户列表 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> show users </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看所有用户 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.printCollectionStats() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看各collection的状态 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.printReplicationInfo() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看主从复制状态 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> show profile </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看profiling </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.copyDatabase('mail_addr','mail_addr_tmp') </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 拷贝数据库 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db.users.dataSize() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查看collection数据的大小 </td> 
 </tr> 
 <tr style="border-width:0px; padding:0px; margin:0px; list-style:none"> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> &nbsp; </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> db. users.totalIndexSize() </td> 
 <td style="border-width:0px; padding:0px; margin:0px; list-style:none"> 查询索引的大小 </td> 
 </tr> 
 </tbody> 
</table>

mongodb语法说明

mongodb语法很多，比如多列索引，查询时可以统计函数，支持多条件查询，但是目前对多表的查询是不支持的，可以想办法通过数据冗余来解决多表查询的问题。举例如下所示。

查询colls所有数据 
db.colls.find() //select \* from colls 
通过指定条件查询 
db.colls.find(\{‘last\_name': ‘Smith'\});//select \* from colls where last\_name='Smith' 
指定多条件查询 
db.colls.find( \{ x : 3, y : “foo” \} );//select \* from colls where x=3 and y='foo' 
 
指定条件范围查询 
db.colls.find(\{j: \{$ne: 3\}, k: \{$gt: 10\} \});//select \* from colls where j!=3 and k>10 
 
查询不包括某内容 
db.colls.find(\{\}, \{a:0\});//查询除a为0外的所有数据 
 
支持<, <=, >, >=查询，需用符号替代分别为$lt，$lte，$gt，$gte 
db.colls.find(\{ “field” : \{ $gt: value \} \} ); 
db.colls.find(\{ “field” : \{ $lt: value \} \} ); 
db.colls.find(\{ “field” : \{ $gte: value \} \} ); 
db.colls.find(\{ “field” : \{ $lte: value \} \} ); 
 
也可对某一字段做范围查询 
db.colls.find(\{ “field” : \{ $gt: value1, $lt: value2 \} \} ); 
 
不等于查询用字符$ne 
db.colls.find( \{ x : \{ $ne : 3 \} \} ); 
 
in查询用字符$in 
db.colls.find( \{ “field” : \{ $in : array \} \} ); 
db.colls.find(\{j:\{$in: \[2,4,6\]\}\}); 
 
not in查询用字符$nin 
db.colls.find(\{j:\{$nin: \[2,4,6\]\}\}); 
 
取模查询用字符$mod 
db.colls.find( \{ a : \{ $mod : \[ 10 , 1 \] \} \} )// where a % 10 == 1 
 
$all查询 
db.colls.find( \{ a: \{ $all: \[ 2, 3 \] \} \} );//指定a满足数组中任意值时 
 
$size查询 
db.colls.find( \{ a : \{ $size: 1 \} \} );//对对象的数量查询，此查询查询a的子对象数目为1的记录 
 
$exists查询 
db.colls.find( \{ a : \{ $exists : true \} \} ); // 存在a对象的数据 
db.colls.find( \{ a : \{ $exists : false \} \} ); // 不存在a对象的数据 
 
$type查询$type值为bsonhttp://bsonspec.org/数 据的类型值 
db.colls.find( \{ a : \{ $type : 2 \} \} ); // 匹配a为string类型数据 
db.colls.find( \{ a : \{ $type : 16 \} \} ); // 匹配a为int类型数据 
 
使用正则表达式匹配 
db.colls.find( \{ name : /acme.\*corp/i \} );//类似于SQL中like 
 
内嵌对象查询 
db.colls.find( \{ “author.name” : “joe” \} ); 
 
1.3.3版本及更高版本包含$not查询 
db.colls.find( \{ name : \{ $not : /acme.\*corp/i \} \} ); 
db.colls.find( \{ a : \{ $not : \{ $mod : \[ 10 , 1 \] \} \} \} ); 
 
sort()排序 
db.colls.find().sort( \{ ts : -1 \} );//1为升序2为降序 
 
limit()对限制查询数据返回个数 
db.colls.find().limit(10) 
 
skip()跳过某些数据 
db.colls.find().skip(10) 
 
snapshot()快照保证没有重复数据返回或对象丢失 
 
count()统计查询对象个数 
db.students.find(\{‘address.state' : ‘CA'\}).count();//效率较高 
db.students.find(\{‘address.state' : ‘CA'\}).toArray().length;//效率很低 
 
group()对查询结果分组和SQL中group by函数类似 
distinct()返回不重复值