1. 准备工作
(1)启动mongo
进入mongo安装目录的bin/ 目录 ， ./mongod
(2)启动mongo客户端
./mongo
(3) 查看所有库
show dbs;
(4) 切换到lvyf库
use lvyf
(5) 查看所有的集合
show collections;
(6)从一个集合中查数据
db.first_col.find();
2. 查询
(1) 查看所有 , pretty() 作用就是格式化json数据
db.collection_name.find().pretty();
> db.first_col.find()
{ "_id" : ObjectId("575e879380d09b176a58ce64"), "name" : "lvyafei", "age" : 21, "sex" : "M", "address" : "http://www.lvyf.com" }
{ "_id" : ObjectId("575e880980d09b176a58ce65"), "name" : "chenjl", "age" : 20, "sex" : "W", "address" : "http://www.chenjl.com" }
{ "_id" : ObjectId("575e889880d09b176a58ce66"), "name" : "child", "age" : 2, "sex" : "M", "address" : "http://www.child.com", "status" : "cry and laugh" }
(2) 条件查询
|
操作 |
格式 | 例子 | 对应的sql语句 |
|
等于 |
{ key : value } | {name : lvyf } | where name='lvyf' |
|
小于 |
{key : {< : value } } | {age : {< : 20 } } | where age < 20 |
|
小于或等于 |
{key : {<e : value }} | {age : {<e : 20 }} | where age <=20 |
|
大于 |
{key : { > : value }} | {age : {> : 3}} | where age > 3 |
|
大于或等于 |
{key : {>e : vlaue }} | {age : {>e : 3 }} | where age >=3 |
| 不等于 | {key : {&ne : value }} | {name : {&ne : lvyf }} |
where name !='lvyf' |
（3）and 条件
根据性别和名字查询记录 ， 对应sql语句where name= 'lvyafei' and sex = 'M'
> db.first_col.find({name : "lvyafei" , sex : "M"}).pretty()
{
"_id" : ObjectId("575e879380d09b176a58ce64"),
"name" : "lvyafei",
"age" : 21,
"sex" : "M",
"address" : "http://www.lvyf.com"
}
(4) or 条件,语法
db.collection_name.find( { $or :[
{key1 : value1} , {key2 : value2 }
] } );
根据名字或者性别查询例子：
> db.first_col.find({$or : [ {name:"lvyafei" },{sex : 'M'}] })
{ "_id" : ObjectId("575e879380d09b176a58ce64"), "name" : "lvyafei", "age" : 21, "sex" : "M", "address" : "http://www.lvyf.com" }
{ "_id" : ObjectId("575e889880d09b176a58ce66"), "name" : "child", "age" : 2, "sex" : "M", "address" : "http://www.child.com", "status" : "cry and laugh" }
(5) and 和 or 联合使用，相当于 where age >= 3 and ( name='lvyafei' or sex='M' )
> db.first_col.find({age : {$gte : 3}, $or:[{name:"lvyafei"} , {set : 'M'}]}).pretty()
{
"_id" : ObjectId("575e879380d09b176a58ce64"),
"name" : "lvyafei",
"age" : 21,
"sex" : "M",
"address" : "http://www.lvyf.com"
}
(6) 大于和小于联合查询，相当于 where age > 3 and age < 21
> db.first_col.find({"age" : {$lt : 21,$gt:3}})
{ "_id" : ObjectId("575e880980d09b176a58ce65"), "name" : "chenjl", "age" : 20, "sex" : "W", "address" : "http://www.chenjl.com" }
(7) $type操作符
如果要查询 name 是string 类型的记录
> db.first_col.find({name : {$type : 2}});
{ "_id" : ObjectId("575e879380d09b176a58ce64"), "name" : "lvyafei", "age" : 21, "sex" : "M", "address" : "http://www.lvyf.com" }
{ "_id" : ObjectId("575e880980d09b176a58ce65"), "name" : "chenjl", "age" : 20, "sex" : "W", "address" : "http://www.chenjl.com" }
{ "_id" : ObjectId("575e889880d09b176a58ce66"), "name" : "child", "age" : 2, "sex" : "M", "address" : "http://www.child.com", "status" : "cry and laugh" }