# 对age%3==1的取模结果

> db.foo.find({'age':{'$mod':[3,1]}},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 186 ] } }

6.使用in, not in ($in, $nin)

#名字不是siwa且年龄在[15，25，85]

> db.foo.find({'name':{'$nin':['siwa']},'age':{'$in':[15,25,85]}},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 186 ] } }

7.匹配null操作

#名字是null的

> db.foo.find({'name':null},{'_id':0})
> 

8.使用like (mongoDB 支持正则表达式)

#名字like%iwa%的 #名字like yi%的

> db.foo.find({'name':/iwa/},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "siwa", "age" : 15, "user" : { "phone" : [ 63, 137 ] } }
> db.foo.find({'name':/^yi/},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }

9.使用distinct、count查询

> db.foo.distinct('name')
[ "yiwa", "erwa", "sanwa", "siwa" ]
> db.foo.count()
4

#distinct结合条件，排序使用

> db.foo.find({},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "erwa", "age" : 95, "user" : { "phone" : [ 123, 133, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 133, 137, 186 ] } }
> db.foo.distinct("age",{'user.phone':{'$in':[63,65,186]}}).sort({'age':1})
[ 25, 85, 95 ]
> db.foo.distinct("age",{'user.phone':{'$in':[63,65,186]}}).sort({'age':-1})
[ 25, 85, 95 ]
> db.foo.distinct("age",{'user.phone':{'$in':[63,65,186]}})
[ 25, 95, 85 ]

待解疑问：？为什么 排序时候 age ：-1 与 age ：1 结果一样？

10.数组查询 （mongoDB自己特有的）（all,size）

#电话中含有186的

> db.foo.find({'user.phone':186},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "erwa", "age" : 75, "user" : { "phone" : [ 63, 188, 13, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 186 ] } }

#电话中含有188，186的

> db.foo.find({'user.phone':{'$all':[188,186]}},{'_id':0})
{ "name" : "erwa", "age" : 75, "user" : { "phone" : [ 63, 188, 13, 186 ] } }

#电话中有2个值的

> db.foo.find({'user.phone':{'$size':2}},{'_id':0})
{ "name" : "siwa", "age" : 15, "user" : { "phone" : [ 63, 137 ] } }

11.exists判断是否存在，type判断类型,Sort排序

#name中值是字符型，age中值是整型，按name升序，age降序

> db.foo.find({'name':{'$type':2},'age':{'$type':16}},{'_id':0}).sort({'name':1,'age':-1})
{ "name" : "erwa", "age" : 75, "user" : { "phone" : [ 63, 188, 13, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 186 ] } }
{ "name" : "siwa", "age" : 15, "user" : { "phone" : [ 63, 137 ] } }

#name中值存在的：true #name中值不存在的：false

> db.foo.find({'name':{'$exists':true}},{'_id':0})
{ "name" : "yiwa", "age" : 25, "user" : { "phone" : [ 123, 13, 186 ] } }
{ "name" : "erwa", "age" : 75, "user" : { "phone" : [ 63, 188, 13, 186 ] } }
{ "name" : "sanwa", "age" : 85, "user" : { "phone" : [ 186 ] } }
{ "name" : "siwa", "age" : 15, "user" : { "phone" : [ 63, 137 ] } }
> db.foo.find({'name':{'$exists':false}},{'_id':0})
> 

12.$elemMatch数组元素匹配

#插入测试数据

> db.foo.save({x:[{'a':1,'b':5},999,'liw',{'a':12},{'b':100}]})
WriteResult({ "nInserted" : 1 })

#查询某元素中a=1，b=5的元素