mongDB--零碎知识搜集

来源：互联网发布：linux nat 配置编辑：程序博客网时间：2024/06/06 02:38

启动mongo

[root@localhost bin]# ./mongod --fork --dbpath=/data/mongoCluster/master/data --port=27017 --logpath=/data/mongoCluster/master/mongodb-linux-i686-3.2.6/log --journal

日期查询

db.liveEpgUserVisits.find({"inputTime":{$gte:ISODate("2014-09-15T00:00:00Z"),$lte:ISODate("2014-09-16T00:00:00Z")}}).count();

mapreduce进行SUM操作

res = db.runCommand({    mapreduce:'liveEpgUserVisits',    map:function() {        emit({provice:this.provice}, {"data":[{"mac":this.mac}],"visit":this.visit});    },    reduce:function(key, value) {        var ret = {data:[]}, visit=0;        var macs = {};        var sum = 0;        for(var i in value) {            var ia = value[i];            for(var j in ia.data) {                if(!macs[ia.data[j].mac]) {                    macs[ia.data[j].mac] = true;                    ret.data.push(ia.data[j]);                }            }           sum += Number(ia.visit);        }        ret.visit = sum;        return ret;    },    query:{"mac":"9ad8f378121cbe8d56f6cfe5b7edcbd1"},    finalize:function(key, values){        return [{count:values.data.length},{visit:values.visit}];    },    out:'tmp_mo_spcode_consignid_1',    verbose:true})

去重统计

db.runCommand({"distinct":"liveEpgUserVisits201501","key":"mac"}).values.length();

详见：http://y-zjx.iteye.com/blog/1313826

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