如何使用mongoDB从集合中找到不同的(和最大的)值?
我有以下收藏-如何使用mongoDB从集合中找到不同的(和最大的)值?,mongodb,Mongodb,我有以下收藏- [{ "customerId" : "54a32e9f1e14fa5476d654db", "hostId" : "192.168.20.20", "runtimeMilliSeconds" : 1422007201815 } { "customerId" : "54a32e9f1e14fa5476d654db", "hostId" : "192.168.20.20", "runtimeMilliSeconds" : 1422008
[{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.20",
"runtimeMilliSeconds" : 1422007201815
}
{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.20",
"runtimeMilliSeconds" : 1422008101736
}
{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.21",
"runtimeMilliSeconds" : 1422009002239
}
{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.21",
"runtimeMilliSeconds" : 1422009901379
}
{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.22",
"runtimeMilliSeconds" : 1422010801685
}
{
"customerId" : "54a32e9f1e14fa5476d654db",
"hostId" : "192.168.20.22",
"runtimeMilliSeconds" : 1422010801585
}]
我还有hostid列表:[“192.168.20.20”、“192.168.20.21”、“192.168.20.22”]
我想将hostId列表与集合匹配,并查找最新(最大)的运行时毫秒数,仅获得以下输出-
[{"hostId":"192.168.20.20", "runtime": 1422007201815},
{"hostId":"192.168.20.21", "runtime": 1422009002239},
{"hostId":"192.168.20.22", "runtime": 1422010801685}]
我已经尝试过跟随mongo聚合-
{ "$match" : { "hostId" : { "$in" : [ "192.168.20.20" , "192.168.20.21" , "192.168.20.22"]} ,
"customerId" : "54a32e9f1e14fa5476d654db"}},
{ "$sort" : { "runtimeMilliSeconds" : -1}},
{ "$group" : { "_id" : { "hostId" : "$hostId" ,
"runtime" : "$runtimeMilliSeconds"}}},
{ "$project" : { "hostId" : "$_id.hostId" ,
"runtimeMilliSeconds" : "$_id.runtime" , "_id" : 0}}
但它给了我集合中的所有值
如何使用mongo获得上述输出???您好,我认为您已经接近您的答案,但以下一些更改将满足您的输出要求
{
"$match": {
"hostId": {
"$in": [
"192.168.20.20",
"192.168.20.21",
"192.168.20.22"
]
},
"customerId": "54a32e9f1e14fa5476d654db"
}
},
{
"$group": {
"_id": {
"hostId": "$hostId",
"runtime": "$runtimeMilliSeconds"
}
}
},
{
"$sort": {
"_id.runtime": -1
}
}{
"$group": {
"_id": "$_id.hostId",
"runtime": {
"$first": "$_id.runtime"
}
}
}
您好,我认为您已接近您的答案,但以下一些更改将满足您的输出
{
"$match": {
"hostId": {
"$in": [
"192.168.20.20",
"192.168.20.21",
"192.168.20.22"
]
},
"customerId": "54a32e9f1e14fa5476d654db"
}
},
{
"$group": {
"_id": {
"hostId": "$hostId",
"runtime": "$runtimeMilliSeconds"
}
}
},
{
"$sort": {
"_id.runtime": -1
}
}{
"$group": {
"_id": "$_id.hostId",
"runtime": {
"$first": "$_id.runtime"
}
}
}
使用运算符
输出将是:
{
"result" : [
{
"hostId" : "192.168.20.20",
"runtimeMilliSeconds" : 1422008101736
},
{
"hostId" : "192.168.20.21",
"runtimeMilliSeconds" : 1422009901379
},
{
"hostId" : "192.168.20.22",
"runtimeMilliSeconds" : 1422010801685
}
],
"ok" : 1
}
使用运算符
输出将是:
{
"result" : [
{
"hostId" : "192.168.20.20",
"runtimeMilliSeconds" : 1422008101736
},
{
"hostId" : "192.168.20.21",
"runtimeMilliSeconds" : 1422009901379
},
{
"hostId" : "192.168.20.22",
"runtimeMilliSeconds" : 1422010801685
}
],
"ok" : 1
}
最有效的方法是使用操作符(不需要$sort stage):
最有效的方法是使用操作符(不需要$sort stage):